How to use the spread operator to flatten array of objects in javascript

Question

I have this array of objects [{x:0, y:1}, {x:3, y:2}] in javascript.

I want to to get an array of x only (0, 3) using the spread operator ... so I can apply javascript Math.max after.

Niet the Dark Absol · Accepted Answer · 2019-05-17 13:47:07Z

5

You don't want to spread, though, you want to map (and then spread the result). So do that:

Math.max(...input.map(_=>_.x));

answered May 17, 2019 at 13:47

Niet the Dark Absol

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1 Comment

karlos Over a year ago

Thank you, I try to assign this expression to a variable then find the max and min but it tells me it is a syntax error. var vector = ...input.map(=>.x) Math.max(vector) Math.min(vector)

Suraj Prakash Sahu · Accepted Answer · 2019-05-17 14:08:20Z

0

You can use ES6 lambda function to achieve this. Please refer code below.

var input = [{"x":1,"y":2},{"x":3,"y":5},{"x":2,"y":2}];
console.log( Math.max( ...input.map(function(a){return a.x} ) ) );

answered May 17, 2019 at 14:08

Suraj Prakash Sahu

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1 Comment

adiga Over a year ago

How is this different than what is already posted? Please don't add unnecessary noise. And there is no lambda function in your code.

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