As of 2016, you’re supposed to use Array.findIndex
(an ES2015/ES6 standard) for this:
a = [
{prop1:"abc",prop2:"qwe"},
{prop1:"bnmb",prop2:"yutu"},
{prop1:"zxvz",prop2:"qwrq"}];
index = a.findIndex(x => x.prop2 ==="yutu");
console.log(index);
It’s supported in Google Chrome, Firefox and Edge. For Internet Explorer, there’s a polyfill on the linked page.
Performance note
Function calls are expensive, therefore with really big arrays a simple loop will perform much better than findIndex
:
let test = [];
for (let i = 0; i < 1e6; i++)
test.push({prop: i});
let search = test.length - 1;
let count = 100;
console.time('findIndex/predefined function');
let fn = obj => obj.prop === search;
for (let i = 0; i < count; i++)
test.findIndex(fn);
console.timeEnd('findIndex/predefined function');
console.time('findIndex/dynamic function');
for (let i = 0; i < count; i++)
test.findIndex(obj => obj.prop === search);
console.timeEnd('findIndex/dynamic function');
console.time('loop');
for (let i = 0; i < count; i++) {
for (let index = 0; index < test.length; index++) {
if (test[index].prop === search) {
break;
}
}
}
console.timeEnd('loop');
As with most optimizations, this should be applied with care and only when actually needed.