-
-
Save gaearon/08a85a33e3d08f3f2ca25fb17bd9d638 to your computer and use it in GitHub Desktop.
strictEquals.js
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
// Your scientists were so preoccupied | |
// with whether or not they could, | |
// they didn't stop to think if they should. | |
// Like a === b | |
function strictEquals(a, b) { | |
if (Object.is(a, b)) { | |
// Same value. | |
// Is this NaN? | |
if (Object.is(a, NaN)) { // We already know a and b are the same, so it's enough to check a. | |
// Special case #1. | |
return false; | |
} else { | |
// They are equal! | |
return true; | |
} | |
} else { | |
// Different value. | |
// Are these 0 and -0? | |
if ( | |
(Object.is(a, 0) && Object.is(b, -0)) || | |
(Object.is(a, -0) && Object.is(b, 0)) | |
) { | |
// Special case #2. | |
return true; | |
} else { | |
// They are not equal! | |
return false; | |
} | |
} | |
} |
function strictEquals(a,b){
if(typeof a === 'number' && typeof b === 'number'){
return a == b
}
return Object.is(a,b)
}
I couldn't figure it out on my own so I looked at your version and tried to minimize (not simplify!) it to the best of my ability
const strictEquals = (a,b) => (Object.is(a,b)
? !Object.is(a, NaN)
: (Object.is(a, 0) && Object.is(b, -0)) || (Object.is(a, -0) && Object.is(b, 0)))
}
function strictEquals(a, b) {
if(Object.is(a, NaN) && Object.is(b, NaN)) return false;
if(Object.is(a, -0) && Object.is(b, 0)) return true;
if(Object.is(b, -0) && Object.is(a, 0)) return true;
return Object.is(a, b);
}
function strictEquals(a,b){
if(Number.isNaN(a)&&Number.isNaN(b)){
return false;
}
if(Number.isFinite(a) && Number.isFinite(b) && Math.abs(a)===0 && Math.abs(b)===0){
return true;
}
return Obejct.is(a,b);
}
const strictEquals = (a, b) => {
if (Object.is(a, NaN) && Object.is(NaN, b)) {
return false;
} else if (Object.is(a, 0) && Object.is(a, -0)) {
return true
} else if (Object.is(a, -0) && Object.is(b, 0)) {
return true
}
return Object.is(a,b)
}
const strictEquals = (a, b) => {
const isSameValue = Object.is(a, b)
// === behaves as same as Object.is() checks the both args are of same value or not
// edge cases
// 0 === -0 || -0 === 0 // true
// NaN === NaN // false
if(isSameValue && Object.is(a, NaN)){
return false
}
if((Object.is(a , 0) && Object.is(b, -0)) || (Object.is(a, -0) && Object.is(b, 0))){
return true
}
return isSameValue
}
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
I found it interesting that you managed to shorten
if (isNaN(a) && isNaN(b)) return false
toif (isNaN(a)) return false
. You don't need to check if either value is NaN, you have enough with checking if the first value is NaN, in which case it will definitely evaluate to false. And you don't need to care about the remaining case in which b is NaN while a isn't, because Object.is() will handle it perfectly.