source: frontend/node_modules/tapable/lib/HookMap.js

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

const util = require("util");

const defaultFactory = (key, hook) => hook;

class HookMap {
        constructor(factory, name = undefined) {
                this._map = new Map();
                this.name = name;
                this._factory = factory;
                this._interceptors = [];
        }

        get(key) {
                return this._map.get(key);
        }

        for(key) {
                // Hot path: inline the map lookup to skip the `this.get(key)`
                // indirection. This gets hit on every hook access in consumers
                // like webpack.
                const map = this._map;
                const hook = map.get(key);
                if (hook !== undefined) {
                        return hook;
                }
                let newHook = this._factory(key);
                const interceptors = this._interceptors;
                for (let i = 0; i < interceptors.length; i++) {
                        newHook = interceptors[i].factory(key, newHook);
                }
                map.set(key, newHook);
                return newHook;
        }

        intercept(interceptor) {
                this._interceptors.push(
                        Object.assign(
                                {
                                        factory: defaultFactory
                                },
                                interceptor
                        )
                );
        }
}

HookMap.prototype.tap = util.deprecate(function tap(key, options, fn) {
        return this.for(key).tap(options, fn);
}, "HookMap#tap(key,…) is deprecated. Use HookMap#for(key).tap(…) instead.");

HookMap.prototype.tapAsync = util.deprecate(function tapAsync(
        key,
        options,
        fn
) {
        return this.for(key).tapAsync(options, fn);
}, "HookMap#tapAsync(key,…) is deprecated. Use HookMap#for(key).tapAsync(…) instead.");

HookMap.prototype.tapPromise = util.deprecate(function tapPromise(
        key,
        options,
        fn
) {
        return this.for(key).tapPromise(options, fn);
}, "HookMap#tapPromise(key,…) is deprecated. Use HookMap#for(key).tapPromise(…) instead.");

module.exports = HookMap;