js Set All In One

交集、并集、补集、差集


function es5Set () {
    this.items = [];
    this.size = this.items.length;
    this.has = function (value) {
        if(this.items.includes(value)) {
            return true;
        } else {
            return false;
        }
    };
    this.add = function (value) {
        if(!this.has(value)) {
            this.items.push(value);
        }
        return this;
    };
    this.delete = function (value) {
        const index = this.items.indexOf(value);
        // const index = this.items.findIndex(item => item === value);
        this.items.splice(index, 1);
    };
    this.clear = function () {
        this.items = [];
    };
    this.values = function () {
        return this.items;
    };
    this.keys = function () {
        return this.values();
    };
    this.entries = function () {
        const matrix = [];
        for (const [index, item] of this.items.entries()) {
            matrix.push([
                index,
                item,
            ]);
        }
        return matrix;
    };
    this.forEach = function (callbackFn, thisArg) {
        for (const item of this.items) {
            const obj = {
                value: item,
                key: item,
                set: this,
            };
            callbackFn(obj, this.arguments);
        }
    };
    // TODO: 交集、并集、补集、差集 (ES6 static 方法 / ES5 prototype 方法)
    this.prototype.intersection  = function () {
        // 
    };
    this.union  = function () {
        // 
    };
    this.complement  = function () {
        // 
    };
    this.difference  = function () {
        // 
    };
}

es5Set.prototype.intersection  = function () {
    // 
};

MDN Set

Set forEach

The forEach() method executes a provided function once for each value in the Set object, in insertion order.

Set.prototype.forEach()


const log = console.log;

const set = new Set(['foo', 'bar', undefined]);

const es6Log = (value, key, set) => {
  log('\n');
  log('ES6: value, key, set =', value, key, set);
  log('ES6: this.arguments', this.arguments);
};

set.forEach(es6Log, this.arguments);

log('\n\n');

function es5Log(value, key, set) {
  log('\n');
  log('ES5: value, key, set =', value, key, set);
  log('ES5: this.arguments', this.arguments);
}

set.forEach(es5Log, this.arguments);