bbo/is.js

bbo is a utility library of zero dependencies for javascript.

'use strict';

/* eslint-disable no-self-compare */
function is(x, y) {
  // inlined Object.is polyfill to avoid requiring consumers ship their own
  // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/is
  if (x === y) {
    // Steps 1-5, 7-10
    // Steps 6.b-6.e: +0 != -0
    // Added the nonzero y check to make Flow happy, but it is redundant
    return x !== 0 || y !== 0 || 1 / x === 1 / y;
  } else {
    // Step 6.a: NaN == NaN
    return x !== x && y !== y;
  }
}

module.exports = is;