Run results for: Iterator with Array#pop() vs iterator with Array#shift()

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:96.0) Gecko/20100101 Firefox/96.0

Browser: Firefox 96

Operating system: Linux

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
Array#pop()	155.9 Ops/sec
Array#shift()	176.7 Ops/sec

Tests:

Array#pop()
const objPop = { a: 1, b: 2, c: 3, [Symbol.iterator]() { const elements = Object.entries( this ).reverse(); // 1 let index = elements.length - 1; return { next() { if ( index >= 0 ) { index--; const [ k, v ] = elements.pop(); // 2 return { value: { k, v }, done: false }; } return { value: undefined, done: true }; } } } }; let i = 0; while ( i++ < 10000 ) { [ ...objPop ]; }
Array#shift()
const objShift = { a: 1, b: 2, c: 3, [Symbol.iterator]() { const elements = Object.entries( this ); return { next() { if ( elements.length > 0 ) { const [ k, v ] = elements.shift(); return { value: { k, v }, done: false }; } return { value: undefined, done: true }; } } } }; let i = 0; while ( i++ < 10000 ) { [ ...objShift ]; }