webpack/lib/dependencies/ContextDependencyHelpers.js

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/
"use strict";

const ContextDependencyHelpers = exports;

/**
 * Escapes regular expression metacharacters
 * @param {string} str String to quote
 * @return {string} Escaped string
 */
const quotemeta = str => {
	return str.replace(/[-[\]\\/{}()*+?.^$|]/g, "\\$&");
};

ContextDependencyHelpers.create = (Dep, range, param, expr, options, contextOptions) => {
	let dep;
	let prefix;
	let postfix;
	let prefixRange;
	let valueRange;
	let idx;
	let context;
	let regExp;
	if(param.isTemplateString()) {
		prefix = param.quasis[0].string;
		postfix = param.quasis.length > 1 ? param.quasis[param.quasis.length - 1].string : "";
		prefixRange = [param.quasis[0].range[0], param.quasis[0].range[1]];
		valueRange = param.range;
		idx = prefix.lastIndexOf("/");
		context = ".";
		if(idx >= 0) {
			context = prefix.substr(0, idx);
			prefix = `.${prefix.substr(idx)}`;
		}
		// If there are more than two quasis, maybe the generated RegExp can be more precise?
		regExp = new RegExp(`^${quotemeta(prefix)}${options.wrappedContextRegExp.source}${quotemeta(postfix)}$`);
		dep = new Dep(Object.assign({
			request: context,
			recursive: options.wrappedContextRecursive,
			regExp,
			mode: "sync"
		}, contextOptions), range, valueRange);
		dep.loc = expr.loc;
		dep.replaces = [{
			range: prefixRange,
			value: prefix
		}];
		dep.critical = options.wrappedContextCritical && "a part of the request of a dependency is an expression";
		return dep;
	} else if(param.isWrapped() && (param.prefix && param.prefix.isString() || param.postfix && param.postfix.isString())) {
		prefix = param.prefix && param.prefix.isString() ? param.prefix.string : "";
		postfix = param.postfix && param.postfix.isString() ? param.postfix.string : "";
		prefixRange = param.prefix && param.prefix.isString() ? param.prefix.range : null;
		valueRange = [prefixRange ? prefixRange[1] : param.range[0], param.range[1]];
		idx = prefix.lastIndexOf("/");
		context = ".";
		if(idx >= 0) {
			context = prefix.substr(0, idx);
			prefix = `.${prefix.substr(idx)}`;
		}
		regExp = new RegExp(`^${quotemeta(prefix)}${options.wrappedContextRegExp.source}${quotemeta(postfix)}$`);
		dep = new Dep(Object.assign({
			request: context,
			recursive: options.wrappedContextRecursive,
			regExp,
			mode: "sync"
		}, contextOptions), range, valueRange);
		dep.loc = expr.loc;
		dep.prepend = param.prefix && param.prefix.isString() ? prefix : null;
		dep.critical = options.wrappedContextCritical && "a part of the request of a dependency is an expression";
		return dep;
	} else {
		dep = new Dep(Object.assign({
			request: options.exprContextRequest,
			recursive: options.exprContextRecursive,
			regExp: options.exprContextRegExp,
			mode: "sync"
		}, contextOptions), range, param.range);
		dep.loc = expr.loc;
		dep.critical = options.exprContextCritical && "the request of a dependency is an expression";
		return dep;
	}
};