Python's operator.eq in TypeScript

How to use

Install via yarn add locutus and import: import { eq } from 'locutus/python/operator/eq'.

Or with CommonJS: const { eq } = require('locutus/python/operator/eq')

Use a bundler that supports tree-shaking so you only ship the functions you actually use. Vite, webpack, Rollup, and Parcel all handle this. For server-side use this is less of a concern.

Examples

These examples are extracted from test cases that automatically verify our functions against their native counterparts.

#	code	expected result
1	eq([1, 2], [1, 2])	true
2	eq(1, true)	true

Notes

• Performs Python-style value equality for plain scalar, array, and object values.

Dependencies

This function uses the following Locutus functions:

• _operator (python/_helpers)

Here's what our current TypeScript equivalent to Python's operator.eq looks like.

TSTypeScript JSJavaScript TSStandalone TS JSStandalone JS

Copy code

import { pythonEqual } from '../_helpers/_operator.ts'

export function eq(a: unknown, b: unknown): boolean {
  //      discuss at: https://locutus.io/python/operator/eq/
  // parity verified: Python 3.12
  //     original by: Kevin van Zonneveld (https://kvz.io)
  //          note 1: Performs Python-style value equality for plain scalar, array, and object values.
  //       example 1: eq([1, 2], [1, 2])
  //       returns 1: true
  //       example 2: eq(1, true)
  //       returns 2: true

  return pythonEqual(a, b)
}

import { pythonEqual } from '../_helpers/_operator.ts'

export function eq(a, b) {
  //      discuss at: https://locutus.io/python/operator/eq/
  // parity verified: Python 3.12
  //     original by: Kevin van Zonneveld (https://kvz.io)
  //          note 1: Performs Python-style value equality for plain scalar, array, and object values.
  //       example 1: eq([1, 2], [1, 2])
  //       returns 1: true
  //       example 2: eq(1, true)
  //       returns 2: true

  return pythonEqual(a, b)
}

// python/_helpers/_operator (Locutus helper dependency)
type NumericLike = number | boolean | bigint

type PythonMapping = { [key: string]: unknown }

function isNumericLike(value: unknown): value is NumericLike {
  return typeof value === 'number' || typeof value === 'boolean' || typeof value === 'bigint'
}

function pythonEqual(left: unknown, right: unknown): boolean {
  if (isNumericLike(left) && isNumericLike(right)) {
    return numericEqual(left, right)
  }

  if (typeof left === 'string' && typeof right === 'string') {
    return left === right
  }

  if (Array.isArray(left) && Array.isArray(right)) {
    if (left.length !== right.length) {
      return false
    }

    return left.every((value, index) => pythonEqual(value, right[index]))
  }

  if (isPythonMapping(left) && isPythonMapping(right)) {
    const leftKeys = Object.keys(left)
    const rightKeys = Object.keys(right)
    if (leftKeys.length !== rightKeys.length) {
      return false
    }

    return leftKeys.every((key) => Object.hasOwn(right, key) && pythonEqual(left[key], right[key]))
  }

  return left === right
}

function numericEqual(left: NumericLike, right: NumericLike): boolean {
  if (typeof left === 'bigint' || typeof right === 'bigint') {
    return bigintEqual(left, right)
  }

  const leftNumber = toComparableNumber(left)
  const rightNumber = toComparableNumber(right)
  return !Number.isNaN(leftNumber) && !Number.isNaN(rightNumber) && leftNumber === rightNumber
}

function toComparableNumber(value: NumericLike): number {
  return typeof value === 'boolean' ? (value ? 1 : 0) : typeof value === 'bigint' ? Number(value) : value
}

function bigintEqual(left: NumericLike, right: NumericLike): boolean {
  const leftBigint = toComparableBigint(left)
  const rightBigint = toComparableBigint(right)
  if (leftBigint === null || rightBigint === null) {
    return false
  }

  return leftBigint === rightBigint
}

function toComparableBigint(value: NumericLike): bigint | null {
  if (typeof value === 'bigint') {
    return value
  }

  if (typeof value === 'boolean') {
    return value ? 1n : 0n
  }

  if (Number.isFinite(value) && Number.isSafeInteger(value)) {
    return BigInt(value)
  }

  return null
}

function isPythonMapping(value: unknown): value is PythonMapping {
  if (typeof value !== 'object' || value === null || Array.isArray(value)) {
    return false
  }

  return Object.prototype.toString.call(value) === '[object Object]'
}

// python/operator/eq (target function module)
function eq(a: unknown, b: unknown): boolean {
  //      discuss at: https://locutus.io/python/operator/eq/
  // parity verified: Python 3.12
  //     original by: Kevin van Zonneveld (https://kvz.io)
  //          note 1: Performs Python-style value equality for plain scalar, array, and object values.
  //       example 1: eq([1, 2], [1, 2])
  //       returns 1: true
  //       example 2: eq(1, true)
  //       returns 2: true

  return pythonEqual(a, b)
}

// python/_helpers/_operator (Locutus helper dependency)
function isNumericLike(value) {
  return typeof value === 'number' || typeof value === 'boolean' || typeof value === 'bigint'
}

function pythonEqual(left, right) {
  if (isNumericLike(left) && isNumericLike(right)) {
    return numericEqual(left, right)
  }

  if (typeof left === 'string' && typeof right === 'string') {
    return left === right
  }

  if (Array.isArray(left) && Array.isArray(right)) {
    if (left.length !== right.length) {
      return false
    }

    return left.every((value, index) => pythonEqual(value, right[index]))
  }

  if (isPythonMapping(left) && isPythonMapping(right)) {
    const leftKeys = Object.keys(left)
    const rightKeys = Object.keys(right)
    if (leftKeys.length !== rightKeys.length) {
      return false
    }

    return leftKeys.every((key) => Object.hasOwn(right, key) && pythonEqual(left[key], right[key]))
  }

  return left === right
}

function numericEqual(left, right) {
  if (typeof left === 'bigint' || typeof right === 'bigint') {
    return bigintEqual(left, right)
  }

  const leftNumber = toComparableNumber(left)
  const rightNumber = toComparableNumber(right)
  return !Number.isNaN(leftNumber) && !Number.isNaN(rightNumber) && leftNumber === rightNumber
}

function toComparableNumber(value) {
  return typeof value === 'boolean' ? (value ? 1 : 0) : typeof value === 'bigint' ? Number(value) : value
}

function bigintEqual(left, right) {
  const leftBigint = toComparableBigint(left)
  const rightBigint = toComparableBigint(right)
  if (leftBigint === null || rightBigint === null) {
    return false
  }

  return leftBigint === rightBigint
}

function toComparableBigint(value) {
  if (typeof value === 'bigint') {
    return value
  }

  if (typeof value === 'boolean') {
    return value ? 1n : 0n
  }

  if (Number.isFinite(value) && Number.isSafeInteger(value)) {
    return BigInt(value)
  }

  return null
}

function isPythonMapping(value) {
  if (typeof value !== 'object' || value === null || Array.isArray(value)) {
    return false
  }

  return Object.prototype.toString.call(value) === '[object Object]'
}

// python/operator/eq (target function module)
function eq(a, b) {
  //      discuss at: https://locutus.io/python/operator/eq/
  // parity verified: Python 3.12
  //     original by: Kevin van Zonneveld (https://kvz.io)
  //          note 1: Performs Python-style value equality for plain scalar, array, and object values.
  //       example 1: eq([1, 2], [1, 2])
  //       returns 1: true
  //       example 2: eq(1, true)
  //       returns 2: true

  return pythonEqual(a, b)
}

Improve this function

Locutus is a community effort following The McDonald's Theory: we ship first iterations, hoping others will improve them. If you see something that could be better, we'd love your contribution.

View on GitHub · Edit on GitHub · View Raw

---

Help us add more

Got a rainy Sunday afternoon and a taste for a porting puzzle?

• Get inspiration from the Python 3 standard library string page.
• Click "New file" in the appropriate folder on GitHub. This will fork the project to your account, directly add the file to it, and send a Pull Request to us.

We will then review it. If it's useful to the project and in line with our contributing guidelines your work will become part of Locutus and you'll be automatically credited in the authors section accordingly.

« More Python operator functions

Star