I want to transform:
[
{id: 1, name: 'one', desc: 'one'},
{id: 2, name: 'two', desc: 'two'},
{id: 3, name: 'three', desc: 'three'}
]
to
{
1: {id: 1, name: 'one', desc: 'one'},
2: {id: 2, name: 'two', desc: 'two'},
3: {id: 3, name: 'three', desc: 'three'}
}
What is the most efficient/performant way to do this? Some options would be:
1) https://github.com/gaearon/normalizr
2) d3.nest()
3) const object = {}; array.forEach(item => { object[item.id] = item });
I like Array.prototype.reduce() solutions. Check this out
var arr = [{id: 1, name: 'one', desc: 'one'}, {id: 2, name: 'two', desc: 'two'}, {id: 3, name: 'three', desc: 'three'}],
obj = arr.reduce((p,c) => {p[c.id] = c; return p},{});
document.write("<pre>" + JSON.stringify(obj,null,2) + "</pre>");You can also use a simple loop:
var arr = [{id: 1, name: 'one', desc: 'one'}, {id: 2, name: 'two', desc: 'two'}, {id: 3, name: 'three', desc: 'three'}],
obj = {}
for(var item of arr) obj[item.id] = item;
Usually loops are faster than ES5 array methods because they don't have to call a function at each iteration.
I would say that it is:
const obj = Object.assign( {}, array );
Although, I haven't compared its performance to your options.
.id not by their index in the array.try this:
ar = [
{id: 1, name: 'one', desc: 'one'},
{id: 2, name: 'two', desc: 'two'},
{id: 3, name: 'three', desc: 'three'}
]
var result = ar.reduce((ac, x) => {return ac[x.id] = x , ac ;}, {})
document.write( JSON.stringify(result) )but remember that the keys are strings and you're dealing with an object not array...
