How to convert an array of arrays to an Object?

Question

What's the best way to convert a list of tuples to a dictionary in javascript?

One way is this:

var data = [['a',1], ['b',2],['c',3]]
var group_to_lengths = {} 

data.forEach(function(d) {
    group_to_lengths[d[0]] = d[1]; 
}); 

Is there a simpler or more idiomatic way of accomplishing the same thing? Perhaps like in python ( group_to_lengths = dict(data) )?

Answer 1

I would recommend using Array.prototype.reduce , which is more idiomatic for this case, like this

console.log(data.reduce(function(result, currentItem) {
    result[currentItem[0]] = currentItem[1];
    return result;
}, {}));
# { a: 1, b: 2, c: 3 }

But, if you use a functional programming library, like underscore.js , then it would be just a one-liner with _.object , like this

console.log(_.object(data));
# { a: 1, b: 2, c: 3 }