mirror of https://github.com/webpack/webpack.git
				
				
				
			
		
			
				
	
	
		
			352 lines
		
	
	
		
			8.1 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
			
		
		
	
	
			352 lines
		
	
	
		
			8.1 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
| /*
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| 	MIT License http://www.opensource.org/licenses/mit-license.php
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| 	Author Tobias Koppers @sokra
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| */
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| 
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| "use strict";
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| 
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| const { SyncHook } = require("tapable");
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| 
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| /**
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|  * @typedef {Object} RuleCondition
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|  * @property {string} property
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|  * @property {boolean} matchWhenEmpty
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|  * @property {function(string): boolean} fn
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|  */
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| 
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| /**
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|  * @typedef {Object} Condition
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|  * @property {boolean} matchWhenEmpty
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|  * @property {function(string): boolean} fn
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|  */
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| 
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| /**
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|  * @typedef {Object} CompiledRule
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|  * @property {RuleCondition[]} conditions
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|  * @property {(Effect|function(object): Effect[])[]} effects
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|  * @property {CompiledRule[]=} rules
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|  * @property {CompiledRule[]=} oneOf
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|  */
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| 
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| /**
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|  * @typedef {Object} Effect
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|  * @property {string} type
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|  * @property {any} value
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|  */
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| 
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| /**
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|  * @typedef {Object} RuleSet
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|  * @property {Map<string, any>} references map of references in the rule set (may grow over time)
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|  * @property {function(object): Effect[]} exec execute the rule set
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|  */
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| 
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| class RuleSetCompiler {
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| 	constructor(plugins) {
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| 		this.hooks = Object.freeze({
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| 			/** @type {SyncHook<[string, object, Set<string>, CompiledRule, Map<string, any>]>} */
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| 			rule: new SyncHook([
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| 				"path",
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| 				"rule",
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| 				"unhandledProperties",
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| 				"compiledRule",
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| 				"references"
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| 			])
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| 		});
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| 		if (plugins) {
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| 			for (const plugin of plugins) {
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| 				plugin.apply(this);
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| 			}
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| 		}
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| 	}
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| 
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| 	/**
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| 	 * @param {object[]} ruleSet raw user provided rules
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| 	 * @returns {RuleSet} compiled RuleSet
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| 	 */
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| 	compile(ruleSet) {
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| 		const refs = new Map();
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| 		const rules = this.compileRules("ruleSet", ruleSet, refs);
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| 
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| 		/**
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| 		 * @param {object} data data passed in
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| 		 * @param {CompiledRule} rule the compiled rule
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| 		 * @param {Effect[]} effects an array where effects are pushed to
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| 		 * @returns {boolean} true, if the rule has matched
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| 		 */
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| 		const execRule = (data, rule, effects) => {
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| 			for (const condition of rule.conditions) {
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| 				const p = condition.property;
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| 				if (p in data) {
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| 					const value = data[p];
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| 					if (!condition.fn(value)) return false;
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| 				} else if (!condition.matchWhenEmpty) {
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| 					return false;
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| 				}
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| 			}
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| 			for (const effect of rule.effects) {
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| 				if (typeof effect === "function") {
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| 					const returnedEffects = effect(data);
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| 					for (const effect of returnedEffects) {
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| 						effects.push(effect);
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| 					}
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| 				} else {
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| 					effects.push(effect);
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| 				}
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| 			}
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| 			if (rule.rules) {
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| 				for (const childRule of rule.rules) {
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| 					execRule(data, childRule, effects);
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| 				}
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| 			}
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| 			if (rule.oneOf) {
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| 				for (const childRule of rule.oneOf) {
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| 					if (execRule(data, childRule, effects)) {
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| 						break;
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| 					}
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| 				}
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| 			}
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| 			return true;
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| 		};
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| 
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| 		return {
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| 			references: refs,
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| 			exec: data => {
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| 				/** @type {Effect[]} */
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| 				const effects = [];
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| 				for (const rule of rules) {
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| 					execRule(data, rule, effects);
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| 				}
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| 				return effects;
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| 			}
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| 		};
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| 	}
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| 
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| 	/**
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| 	 * @param {string} path current path
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| 	 * @param {object[]} rules the raw rules provided by user
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| 	 * @param {Map<string, any>} refs references
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| 	 * @returns {CompiledRule[]} rules
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| 	 */
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| 	compileRules(path, rules, refs) {
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| 		return rules.map((rule, i) =>
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| 			this.compileRule(`${path}[${i}]`, rule, refs)
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| 		);
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| 	}
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| 
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| 	/**
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| 	 * @param {string} path current path
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| 	 * @param {object} rule the raw rule provided by user
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| 	 * @param {Map<string, any>} refs references
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| 	 * @returns {CompiledRule} normalized and compiled rule for processing
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| 	 */
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| 	compileRule(path, rule, refs) {
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| 		const unhandledProperties = new Set(
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| 			Object.keys(rule).filter(key => rule[key] !== undefined)
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| 		);
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| 
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| 		/** @type {CompiledRule} */
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| 		const compiledRule = {
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| 			conditions: [],
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| 			effects: [],
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| 			rules: undefined,
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| 			oneOf: undefined
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| 		};
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| 
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| 		this.hooks.rule.call(path, rule, unhandledProperties, compiledRule, refs);
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| 
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| 		if (unhandledProperties.has("rules")) {
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| 			unhandledProperties.delete("rules");
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| 			const rules = rule.rules;
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| 			if (!Array.isArray(rules))
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| 				throw this.error(path, rules, "Rule.rules must be an array of rules");
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| 			compiledRule.rules = this.compileRules(`${path}.rules`, rules, refs);
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| 		}
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| 
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| 		if (unhandledProperties.has("oneOf")) {
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| 			unhandledProperties.delete("oneOf");
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| 			const oneOf = rule.oneOf;
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| 			if (!Array.isArray(oneOf))
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| 				throw this.error(path, oneOf, "Rule.oneOf must be an array of rules");
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| 			compiledRule.oneOf = this.compileRules(`${path}.oneOf`, oneOf, refs);
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| 		}
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| 
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| 		if (unhandledProperties.size > 0) {
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| 			throw this.error(
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| 				path,
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| 				rule,
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| 				`Properties ${Array.from(unhandledProperties).join(", ")} are unknown`
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| 			);
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| 		}
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| 
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| 		return compiledRule;
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| 	}
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| 
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| 	/**
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| 	 * @param {string} path current path
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| 	 * @param {any} condition user provided condition value
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| 	 * @returns {Condition} compiled condition
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| 	 */
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| 	compileCondition(path, condition) {
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| 		if (!condition) {
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| 			throw this.error(
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| 				path,
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| 				condition,
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| 				"Expected condition but got falsy value"
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| 			);
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| 		}
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| 		if (typeof condition === "string") {
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| 			return {
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| 				matchWhenEmpty: condition.length === 0,
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| 				fn: str => str.startsWith(condition)
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| 			};
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| 		}
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| 		if (typeof condition === "function") {
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| 			try {
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| 				return {
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| 					matchWhenEmpty: condition(""),
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| 					fn: condition
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| 				};
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| 			} catch (err) {
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| 				throw this.error(
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| 					path,
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| 					condition,
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| 					"Evaluation of condition function threw error"
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| 				);
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| 			}
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| 		}
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| 		if (condition instanceof RegExp) {
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| 			return {
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| 				matchWhenEmpty: condition.test(""),
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| 				fn: v => condition.test(v)
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| 			};
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| 		}
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| 		if (Array.isArray(condition)) {
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| 			const items = condition.map((c, i) =>
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| 				this.compileCondition(`${path}[${i}]`, c)
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| 			);
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| 			return this.combineConditionsOr(items);
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| 		}
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| 
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| 		if (typeof condition !== "object") {
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| 			throw this.error(
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| 				path,
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| 				condition,
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| 				`Unexcepted ${typeof condition} when condition was expected`
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| 			);
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| 		}
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| 
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| 		const conditions = [];
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| 		for (const key of Object.keys(condition)) {
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| 			const value = condition[key];
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| 			switch (key) {
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| 				case "or":
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| 					if (value) {
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| 						if (!Array.isArray(value)) {
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| 							throw this.error(
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| 								`${path}.or`,
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| 								condition.and,
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| 								"Expected array of conditions"
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| 							);
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| 						}
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| 						conditions.push(this.compileCondition(`${path}.or`, value));
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| 					}
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| 					break;
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| 				case "and":
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| 					if (value) {
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| 						if (!Array.isArray(value)) {
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| 							throw this.error(
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| 								`${path}.and`,
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| 								condition.and,
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| 								"Expected array of conditions"
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| 							);
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| 						}
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| 						let i = 0;
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| 						for (const item of value) {
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| 							conditions.push(this.compileCondition(`${path}.and[${i}]`, item));
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| 							i++;
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| 						}
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| 					}
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| 					break;
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| 				case "not":
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| 					if (value) {
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| 						const matcher = this.compileCondition(`${path}.not`, value);
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| 						const fn = matcher.fn;
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| 						conditions.push({
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| 							matchWhenEmpty: !matcher.matchWhenEmpty,
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| 							fn: v => !fn(v)
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| 						});
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| 					}
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| 					break;
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| 				default:
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| 					throw this.error(
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| 						`${path}.${key}`,
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| 						condition[key],
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| 						`Unexcepted property ${key} in condition`
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| 					);
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| 			}
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| 		}
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| 		if (conditions.length === 0) {
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| 			throw this.error(
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| 				path,
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| 				condition,
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| 				"Expected condition, but got empty thing"
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| 			);
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| 		}
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| 		return this.combineConditionsAnd(conditions);
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| 	}
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| 
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| 	/**
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| 	 * @param {Condition[]} conditions some conditions
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| 	 * @returns {Condition} merged condition
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| 	 */
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| 	combineConditionsOr(conditions) {
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| 		if (conditions.length === 0) {
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| 			return {
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| 				matchWhenEmpty: false,
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| 				fn: () => false
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| 			};
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| 		} else if (conditions.length === 1) {
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| 			return conditions[0];
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| 		} else {
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| 			return {
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| 				matchWhenEmpty: conditions.some(c => c.matchWhenEmpty),
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| 				fn: v => conditions.some(c => c.fn(v))
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| 			};
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| 		}
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| 	}
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| 
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| 	/**
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| 	 * @param {Condition[]} conditions some conditions
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| 	 * @returns {Condition} merged condition
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| 	 */
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| 	combineConditionsAnd(conditions) {
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| 		if (conditions.length === 0) {
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| 			return {
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| 				matchWhenEmpty: false,
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| 				fn: () => false
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| 			};
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| 		} else if (conditions.length === 1) {
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| 			return conditions[0];
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| 		} else {
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| 			return {
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| 				matchWhenEmpty: conditions.every(c => c.matchWhenEmpty),
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| 				fn: v => conditions.every(c => c.fn(v))
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| 			};
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| 		}
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| 	}
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| 
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| 	/**
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| 	 * @param {string} path current path
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| 	 * @param {any} value value at the error location
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| 	 * @param {string} message message explaning the problem
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| 	 * @returns {Error} an error object
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| 	 */
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| 	error(path, value, message) {
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| 		return new Error(
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| 			`Compiling RuleSet failed: ${message} (at ${path}: ${value})`
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| 		);
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| 	}
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| }
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| 
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| module.exports = RuleSetCompiler;
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