mirror of https://github.com/webpack/webpack.git
28 lines
709 B
JavaScript
28 lines
709 B
JavaScript
|
/*
|
||
|
|
MIT License http://www.opensource.org/licenses/mit-license.php
|
||
|
|
Author Tobias Koppers @sokra
|
||
|
|
*/
|
||
|
|
"use strict";
|
||
|
|
|
||
|
|
const mergeCache = new WeakMap();
|
||
|
|
|
||
|
|
const cachedMerge = (first, ...args) => {
|
||
|
|
if(args.length === 0) return first;
|
||
|
|
if(args.length > 1) {
|
||
|
|
return cachedMerge(first, cachedMerge(...args));
|
||
|
|
}
|
||
|
|
const second = args[0];
|
||
|
|
let innerCache = mergeCache.get(first);
|
||
|
|
if(innerCache === undefined) {
|
||
|
|
innerCache = new WeakMap();
|
||
|
|
mergeCache.set(first, innerCache);
|
||
|
|
}
|
||
|
|
const cachedMerge = innerCache.get(second);
|
||
|
|
if(cachedMerge !== undefined) return cachedMerge;
|
||
|
|
const newMerge = Object.assign({}, first, second);
|
||
|
|
innerCache.set(second, newMerge);
|
||
|
|
return newMerge;
|
||
|
|
};
|
||
|
|
|
||
|
|
module.exports = cachedMerge;
|