Comparison Operation

isArray

isCallable

抽象操作isCallable接受参数argument(es type value)，并且返回一个Boolean。

其判定如果 argument 是一个调用的函数（具有[[Call]]的内部插槽方法），执行以下步骤：

1. if argument is not Object, return false
2. if argument has a [[Call]] internal method, return true
3. return false

具体实现

// https://tc39.es/ecma262/#sec-IsHTMLDDA-internal-slot

import { ESValueType } from "../modules/types/valueType";

// host environment eg. nodejs or browser
const documentAll = typeof document === 'object' && document.all;

// IsHTMLDDA-internal-slot and IsLooselyEqual and ToBoolean
const IsHTMLDDA = typeof documentAll == 'undefined' && documentAll === 'undefined';

export function IsCallable(argument: ESValueType): boolean {

  if(IsHTMLDDA) return typeof argument === 'function' || argument === documentAll;

  return typeof argument === 'function';
}

isConstructor

isExtensible

isLessThan

isStrictlyEqual

抽象操作isStrictlyEqual接受参数 x（ECMAScript语言值）和y（ECMAScript语言值）并返回布尔值或者throw completion。 它为===运算符提供了语义。

它会执行以下步骤：

1. If Type(x) is not Type(y), return false.
2. If x is a Number, then a. Return Number::equal(x, y).
3. Return SameValueNonNumber(x, y).

具体实现Polyfill：

export function isStrictlyEqual(x: ESValueType, y: ESValueType): boolean {
  if(typeof x !== typeof y) return false;

  if(typeof x === 'number' && typeof y === 'number') {
    return numberEqual(x, y);
  }

  return sameValueNonNumber(x as Omit<ESValueType, 'number'>, y as Omit<ESValueType, 'number'>);
}

isLooselyEqual

抽象操作isLooselyEqual接受参数 x（ECMAScript语言值）和 y（ECMAScript语言值）并返回布尔值或者throw completion。

执行以下步骤：

• Type(x) is Type(y), then
  • Return isStrictlyEqual
• If x is null and y is undefined, return true
• If x is undefined and x is null, return true
• Note: internal Slot
  • If x is an Object, x has an [[IsHTMLDDA]] internal slot, and y is either undefined or null, return true
  • If x is either undefined or null, y is an Object, and y has an [[IsHTMLDDA]] internal slot, return true
• If x is a Number and y is a String, return !isLooselyEqual(x, !ToNumber(y))
• If y is a Number and x is a String, return !isLooselyEqual(y, !ToNumber(x))
• If x is a BigInt and y is a String, then
  • Let n be StringToBigInt(y)
  • if n is undefined, return false
  • Return !isLooselyEqual(x, n)
• If x is a String and y is a BigInt, return !isLooselyEqual(y, x)
• If x is a Boolean, return !isLooselyEqual(!ToNumber(x), y)
• If y is a Boolean, return !isLooselyEqual(!ToNumber(y), x)
• If x is either a String, a Number, a BigInt, or a Symbol and y is an Object, return !isLooselyEqual(x, ?ToPrimary(y))
• If y is either a String, a Number, a BigInt, or a Symbol and x is an Object, return !isLooselyEqual(?ToPrimary(x), y)
• If x is a BigInt and y is a Number, or if x is a Number and y is a BigInt, then
  • if x is not finite and y is not finite, return false
  • if ℝ(x) = ℝ(y), return true; otherwise return false.
• Return false

SameValue

抽象操作SameValue接受参数 x（ECMAScript语言值）和x - ECMAScript语言值并返回布尔值。 它决定了这两个参数是否是相同的值。调用时，它会执行以下步骤：

1. If Type(x) is not Type(y), return false.
2. If x is a Number, then a. Return Number::sameValue(x, y).
3. Return SameValueNonNumber(x, y).

具体实现Polyfill：

export function sameValue(x: ESValueType, y: ESValueType): boolean {
  if(typeof x !== typeof y) return false;

  if(typeof x === 'number' && typeof y === 'number') {
    return numberSameValue(x, y);
  }

  return sameValueNonNumber(x as Omit<ESValueType, 'number'>, y as Omit<ESValueType, 'number'>);
}

numberSameValue 又名sameValue

sameValueNonNumber

抽象操作sameValueNonNumber接受参数 x(除Number类型) - ECMAScript语言值和y(除Number类型) - ECMAScript语言值并返回布尔值。 调用时，它会执行以下步骤：

1. Assert: Type(x) is Type(y).
2. If x is either null or undefined, return true.
3. If x is a BigInt, then a. Return BigInt::equal(x, y).
4. If x is a String, then a. If x and y have the same length and the same code units in the same positions, return true; otherwise, return false.
5. If x is a Boolean, then a. If x and y are both true or both false, return true; otherwise, return false.
6. NOTE: All other ECMAScript language values are compared by identity.
7. If x is y, return true; otherwise, return false.

具体实现Polyfill：

export function sameValueNonNumber(x: Omit<ESValueType, 'number'>, y: Omit<ESValueType, 'number'>) {

  // Assert: Type(x) is Type(y).
  if (typeof x !== typeof y) {
    throw new Error("Type of x must be the same as the type of y");
  }

  // If x is either null or undefined, return true.
  if (x === null || x === undefined) {
    return true;
  }

  // If x is a BigInt, then return BigInt::equal(x, y).
  if (typeof x === 'bigint') {
    return BigInt.equal(x, y); // Assuming BigInt has an equal method
  }

  // NOTE: All other ECMAScript language values are compared by identity.
  // If x is y, return true; otherwise, return false.
  return x === y
}

sameValueZero

抽象操作SameValueZero接受参数 x - ECMAScript语言值和x - ECMAScript语言值并返回布尔值。 它决定了两个参数是否是相同的值（忽略+0F和-0F之间的差异）。调用时，它会执行以下步骤：

1. If Type(x) is not Type(y), return false.
2. If x is a Number, then a. Return Number::sameValueZero(x, y).
3. Return SameValueNonNumber(x, y).

export function sameValue(x: ESValueType, y: ESValueType): boolean {
  if(typeof x !== typeof y) return false;

  if(typeof x === 'number' && typeof y === 'number') {
    return numberSameValue(x, y);
  }

  return sameValueNonNumber(x as Omit<ESValueType, 'number'>, y as Omit<ESValueType, 'number'>);
}

numberSameValue 又名sameValue

sameValueNonNumber 是非数值类型的值进行比较，移步

isPropertyKey

isRegExp

抽象操作isRegExp接受参数argument(es type value)，并且返回一个包含Boolean一个normal completion或者throw exception。

执行步骤：

1. if argument is not an Object, return false
2. Let matcher be ? Get(argument, %Symbol.match%).
3. If matcher is not undefined, return (matcher).
4. If argument has a [[RegExpMatcher]] internal slot, return true.