 // test the polyfill
(this.window || global).Map = undefined;
(this.window || global).Set = undefined;
(this.window || global).WeakMap = undefined;
(this.window || global).WeakSet = undefined;


var assert = require('better-assert');
// require('../index');
require('../es6-collections');

describe('ES Collections test', function(){
  it("WeakMap existence", function () {
    assert(WeakMap);
  });

  it("WeakMap constructor behavior", function () {
    assert(new WeakMap instanceof WeakMap);
    assert(new WeakMap() instanceof WeakMap);
    var a = {};
    var b = {};
    var c = new WeakMap();
    var m = new WeakMap([[a,1], [b,2], [c, 3]]);
    assert(m.has(a));
    assert(m.has(b));
    assert(m.has(c));
    if ("__proto__" in {}) {
      assert((new WeakMap).__proto__.isPrototypeOf(new WeakMap()));
      assert((new WeakMap).__proto__ === WeakMap.prototype);
    }
  });

  it("WeakMap#has", function () {
    var
      o = new WeakMap(),
      generic = {},
      callback = function () {}
    ;
    assert(false === o.has(callback));
    o.set(callback, generic);
    assert(true === o.has(callback));
  });

  it("WeakMap#get", function () {
    var
      o = new WeakMap(),
      generic = {},
      callback = function () {}
    ;
    //:was assert(o.get(callback, 123) === 123);
    o.set(callback, generic);
    assert(o.get(callback, 123) === generic);
    assert(o.get(callback) === generic);
  });

  it("WeakMap#set", function () {
    var
      o = new WeakMap(),
      generic = {},
      callback = function () {}
    ;
    o.set(callback, generic);
    assert(o.get(callback) === generic);
    o.set(callback, callback);
    assert(o.get(callback) === callback);
    o.set(callback, o);
    assert(o.get(callback) === o);
    o.set(o, callback);
    assert(o.get(o) === callback);
  });

  it("WeakMap#['delete']", function () {
    var
      o = new WeakMap(),
      generic = {},
      callback = function () {}
    ;
    o.set(callback, generic);
    o.set(generic, callback);
    o.set(o, callback);
    assert(o.has(callback) && o.has(generic) && o.has(o));
    o["delete"](callback);
    o["delete"](generic);
    o["delete"](o);
    assert(!o.has(callback) && !o.has(generic) && !o.has(o));
    assert(o["delete"](o) === false);
    o.set(o, callback);
    assert(o["delete"](o));
  });

  it("non object key throws an error", function () {
    var o = new WeakMap();
    try {
      o.set("key", o);
      assert(false);
    } catch(emAll) {
      assert(true);
    }
  });

  it("Map existence", function () {
    assert(Map);
  });

  it("Map constructor behavior", function () {
    assert(new Map instanceof Map);
    assert(new Map() instanceof Map);
    var a = 1;
    var b = {};
    var c = new Map();
    var m = new Map([[1,1], [b,2], [c, 3]]);
    assert(m.has(a));
    assert(m.has(b));
    assert(m.has(c));
    assert(m.size, 3);
    if ("__proto__" in {}) {
      assert((new Map).__proto__.isPrototypeOf(new Map()));
      assert((new Map).__proto__ === Map.prototype);
    }
  });

  it("Map#size - Mozilla only", function () {
    var
      o = new Map()
    ;
    if ("size" in o) {
      assert(o.size === 0);
      o.set("a", "a");
      assert(o.size === 1);
      o["delete"]("a");
      assert(o.size === 0);
    }
  });

  it("Map#has", function () {
    var
      o = new Map(),
      generic = {},
      callback = function () {}
    ;
    assert(false === o.has(callback));
    o.set(callback, generic);
    assert(true === o.has(callback));
  });

  it("Map#get", function () {
    var
      o = new Map(),
      generic = {},
      callback = function () {}
    ;
    //:was assert(o.get(callback, 123) === 123);
    o.set(callback, generic);
    assert(o.get(callback, 123) === generic);
    assert(o.get(callback) === generic);
  });

  it("Map#set", function () {
    var
      o = new Map(),
      generic = {},
      callback = function () {}
    ;
    o.set(callback, generic);
    assert(o.get(callback) === generic);
    o.set(callback, callback);
    assert(o.get(callback) === callback);
    o.set(callback, o);
    assert(o.get(callback) === o);
    o.set(o, callback);
    assert(o.get(o) === callback);
    o.set(NaN, generic);
    assert(o.has(NaN));
    assert(o.get(NaN) === generic);
    o.set("key", undefined);
    assert(o.has("key"));
    assert(o.get("key") === undefined);

    assert(!o.has(-0));
    assert(!o.has(0));
    o.set(-0, callback);
    assert(o.has(-0));
    assert(o.has(0));
    assert(o.get(-0) === callback);
    assert(o.get(0) === callback);
    o.set(0, generic);
    assert(o.has(-0));
    assert(o.has(0));
    assert(o.get(-0) === generic);
    assert(o.get(0) === generic);
  });

  it("Map#['delete']", function () {
    var
      o = new Map(),
      generic = {},
      callback = function () {}
    ;
    o.set(callback, generic);
    o.set(generic, callback);
    o.set(o, callback);
    assert(o.has(callback) && o.has(generic) && o.has(o));
    o["delete"](callback);
    o["delete"](generic);
    o["delete"](o);
    assert(!o.has(callback) && !o.has(generic) && !o.has(o));
    assert(o["delete"](o) === false);
    o.set(o, callback);
    assert(o["delete"](o));
  });

  it("non object key does not throw an error", function () {
    var o = new Map();
    try {
      o.set("key", o);
      assert(true);
    } catch(emAll) {
      assert(false);
    }
  });

  it("keys, values, entries behavior", function () {
    // test that things get returned in insertion order as per the specs
    var o = new Map([["1", 1], ["2", 2], ["3", 3]]);
    var keys = o.keys(), values = o.values();
    var k = keys.next(), v = values.next();
    assert(k.value === "1" && v.value === 1);
    o.delete("2");
    k = keys.next(), v = values.next();
    assert(k.value === "3" && v.value === 3);
    // insertion of previously-removed item goes to the end
    o.set("2", 2);
    k = keys.next(), v = values.next();
    assert(k.value === "2" && v.value === 2);
    // when called again, new iterator starts from beginning
    var entriesagain = o.entries();
    assert(entriesagain.next().value[0] === "1");
    assert(entriesagain.next().value[0] === "3");
    assert(entriesagain.next().value[0] === "2");
    // after a iterator is finished, don't return any more elements
    k = keys.next(), v = values.next();
    assert(k.done && v.done);
    k = keys.next(), v = values.next();
    assert(k.done && v.done);
    o.set("4", 4);
    k = keys.next(), v = values.next();
    assert(k.done && v.done);
    // new element shows up in iterators that didn't yet finish
    assert(entriesagain.next().value[0] === "4");
    assert(entriesagain.next().done);
  });

  it("Map#forEach", function () {
    var o = new Map(), i;
    o.set("key 0", 0);
    o.set("key 1", 1);
    if ("forEach" in o) {
      o.forEach(function (value, key, obj) {
        assert(key === "key " + value);
        assert(obj === o);
        // even if dropped, keeps looping
        o["delete"](key);
      });
      assert(!o.size);
    }
  });

  it("Map#forEach with mutations", function () {
    var o = new Map([["0", 0], ["1", 1], ["2", 2]]), seen = [];
    o.forEach(function (value, key, obj) {
      seen.push(value);
      assert(obj === o);
      assert(""+value === key);
      // mutations work as expected
      if (value === 1) {
        o.delete("0"); // remove from before current index
        o.delete("2"); // remove from after current index
        o.set("3", 3); // insertion
      } else if (value === 3) {
        o.set("0", 0); // insertion at the end
      }
    });
    assert(JSON.stringify(seen) === JSON.stringify([0, 1, 3, 0]));
    assert(JSON.stringify(o._values) === JSON.stringify([1, 3, 0]));
  });

  it("Map#clear", function(){
    var o = new Map();
    o.set(1, '1');
    o.set(2, '2');
    o.set(3, '3');
    o.clear();
    assert(!o.size);
  });

  it("Set existence", function () {
    assert(Set);
  });

  it("Set constructor behavior", function () {
    assert(new Set instanceof Set);
    assert(new Set() instanceof Set);
    var s = new Set([1,2]);
    assert(s.has(1));
    assert(s.has(2));
    assert(s.size, 2);
    if ("__proto__" in {}) {
      assert((new Set).__proto__.isPrototypeOf(new Set()));
      assert((new Set).__proto__ === Set.prototype);
    }
  });

  it("Set#size - Mozilla only", function () {
    var
      o = new Set()
    ;
    if ("size" in o) {
      assert(o.size === 0);
      o.add("a");
      assert(o.size === 1);
      o["delete"]("a");
      assert(o.size === 0);
    }
  });

  it("Set#add", function () {
    var o = new Set();
    assert(o.add(NaN));
    assert(o.has(NaN));
  });

  it("Set#['delete']", function () {
    var
      o = new Set(),
      generic = {},
      callback = function () {}
    ;
    o.add(callback);
    o.add(generic);
    o.add(o);
    assert(o.has(callback) && o.has(generic) && o.has(o));
    o["delete"](callback);
    o["delete"](generic);
    o["delete"](o);
    assert(!o.has(callback) && !o.has(generic) && !o.has(o));
    assert(o["delete"](o) === false);
    o.add(o);
    assert(o["delete"](o) === true);
  });

  it("values behavior", function () {
    // test that things get returned in insertion order as per the specs
    var o = new Set([1, 2, 3]);
    assert(o.keys === o.values); // same function, as per the specs
    var values = o.values();
    var v = values.next();
    assert(v.value === 1);
    o.delete(2);
    v = values.next();
    assert(v.value === 3);
    // insertion of previously-removed item goes to the end
    o.add(2);
    v = values.next();
    assert(v.value === 2);
    // when called again, new iterator starts from beginning
    var entriesagain = o.entries();
    assert(entriesagain.next().value[1] === 1);
    assert(entriesagain.next().value[1] === 3);
    assert(entriesagain.next().value[1] === 2);
    // after a iterator is finished, don't return any more elements
    v = values.next();
    assert(v.done);
    v = values.next();
    assert(v.done);
    o.add(4);
    v = values.next();
    assert(v.done);
    // new element shows up in iterators that didn't yet finish
    assert(entriesagain.next().value[1] === 4);
    assert(entriesagain.next().done);
  });

  it("Set#has", function () {
    var
      o = new Set(),
      generic = {},
      callback = function () {}
    ;
    assert(false === o.has(callback));
    o.add(callback);
    assert(true === o.has(callback));
  });

  it("Set#forEach", function () {
    var o = new Set(), i = 0;
    o.add("value 0");
    o.add("value 1");
    if ("forEach" in o) {
      o.forEach(function (value, sameValue, obj) {
        assert(value === "value " + i++);
        assert(obj === o);
        assert(value === sameValue);
        // even if dropped, keeps looping
        o["delete"](value);
      });
      assert(!o.size);
    }
  });

  it("Set#forEach with mutations", function () {
    var o = new Set([0, 1, 2]), seen = [];
    o.forEach(function (value, sameValue, obj) {
      seen.push(value);
      assert(obj === o);
      assert(value === sameValue);
      // mutations work as expected
      if (value === 1) {
        o.delete(0); // remove from before current index
        o.delete(2); // remove from after current index
        o.add(3); // insertion
      } else if (value === 3) {
        o.add(0); // insertion at the end
      }
    });
    assert(JSON.stringify(seen) === JSON.stringify([0, 1, 3, 0]));
    assert(JSON.stringify(o._values) === JSON.stringify([1, 3, 0]));
  });

  it("Set#clear", function(){
    var o = new Set();
    o.add(1);
    o.add(2);
    o.clear();
    assert(!o.size);
  });

  it("WeakSet existence", function () {
    assert(WeakSet);
  });

  it("WeakSet constructor behavior", function () {
    assert(new WeakSet instanceof WeakSet);
    assert((new WeakSet) instanceof WeakSet);
    var a = {}, b = {};
    var s = new WeakSet([a, b]);
    assert(s.has(a) && s.has(b));
    if ("__proto__" in {}) {
      assert((new WeakSet).__proto__.isPrototypeOf(new WeakSet()));
      assert((new WeakSet).__proto__ === WeakSet.prototype);
    }
  });

  it("Set#add, WeakSet#add, Map#set and WeakMap#set are chainable now", function(){
    var s = new Set();
    var ws = new WeakSet();
    var m = new Map();
    var wm = new WeakMap();
    var a = {}, b = {};

    s.add(1).add(2);
    assert(s.has(1) && s.has(2) && s.size === 2);

    ws.add(a).add(b);
    assert(ws.has(a) && ws.has(b));

    m.set(1, 1).set(a, 2);
    assert(m.has(1) && m.has(a) && m.size === 2);

    wm.set(a, b).set(b, a);
    assert(wm.get(a) === b && wm.get(b) === a);
  });

  it("Recognize any iterable as the constructor input", function(){
    var a = new Set(new Set([1,2]));
    assert(a.has(1));
  });
});

created 1 year ago by Khalino

Javascript Online Compiler

Write, Run & Share Javascript code online using OneCompiler's JS online compiler for free. It's one of the robust, feature-rich online compilers for Javascript language. Getting started with the OneCompiler's Javascript editor is easy and fast. The editor shows sample boilerplate code when you choose language as Javascript and start coding.

About Javascript

Javascript(JS) is a object-oriented programming language which adhere to ECMA Script Standards. Javascript is required to design the behaviour of the web pages.

Key Features

Open-source
Just-in-time compiled language
Embedded along with HTML and makes web pages alive
Originally named as LiveScript.
Executable in both browser and server which has Javascript engines like V8(chrome), SpiderMonkey(Firefox) etc.

Syntax help

STDIN Example

var readline = require('readline');
var rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
  terminal: false
});

rl.on('line', function(line){
    console.log("Hello, " + line);
});

variable declaration

Keyword	Description	Scope
var	Var is used to declare variables(old way of declaring variables)	Function or global scope
let	let is also used to declare variables(new way)	Global or block Scope
const	const is used to declare const values. Once the value is assigned, it can not be modified	Global or block Scope

Backtick Strings

Interpolation

let greetings = `Hello ${name}`

Multi line Strings

const msg = `
hello
world!
`

Arrays

An array is a collection of items or values.

Syntax:

let arrayName = [value1, value2,..etc];
// or
let arrayName = new Array("value1","value2",..etc);

Example:

let mobiles = ["iPhone", "Samsung", "Pixel"];

// accessing an array
console.log(mobiles[0]);

// changing an array element
mobiles[3] = "Nokia";

Arrow functions

Arrow Functions helps developers to write code in concise way, it’s introduced in ES6.
Arrow functions can be written in multiple ways. Below are couple of ways to use arrow function but it can be written in many other ways as well.

Syntax:

() => expression

Example:

const numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
const squaresOfEvenNumbers = numbers.filter(ele => ele % 2 == 0)
                                    .map(ele => ele ** 2);
console.log(squaresOfEvenNumbers);

De-structuring

Arrays

let [firstName, lastName] = ['Foo', 'Bar']

Objects

let {firstName, lastName} = {
  firstName: 'Foo',
  lastName: 'Bar'
}

rest(...) operator

 const {
    title,
    firstName,
    lastName,
    ...rest
  } = record;

Spread(...) operator

//Object spread
const post = {
  ...options,
  type: "new"
}
//array spread
const users = [
  ...adminUsers,
  ...normalUsers
]

Functions

function greetings({ name = 'Foo' } = {}) { //Defaulting name to Foo
  console.log(`Hello ${name}!`);
}
 
greet() // Hello Foo
greet({ name: 'Bar' }) // Hi Bar

Loops

1. If:

IF is used to execute a block of code based on a condition.

Syntax

if(condition){
    // code
}

2. If-Else:

Else part is used to execute the block of code when the condition fails.

Syntax

if(condition){
    // code
} else {
    // code
}

3. Switch:

Switch is used to replace nested If-Else statements.

Syntax

switch(condition){
    case 'value1' :
        //code
        [break;]
    case 'value2' :
        //code
        [break;]
    .......
    default :
        //code
        [break;]
}

4. For

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
//code  
}

5. While

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while (condition) {  
  // code 
}

6. Do-While

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {  
  // code 
} while (condition);

Classes

ES6 introduced classes along with OOPS concepts in JS. Class is similar to a function which you can think like kind of template which will get called when ever you initialize class.

Syntax:

class className {
  constructor() { ... } //Mandatory Class method
  method1() { ... }
  method2() { ... }
  ...
}

Example:

class Mobile {
  constructor(model) {
    this.name = model;
  }
}

mbl = new Mobile("iPhone");