How to push a single value with Array.push in a two dimensional array?

Asked Feb 23 '19 at 18:04

Active Feb 23 '19 at 18:04

Viewed 34 times

const y = [...Array(2)].map(() => Array(3).fill([]));
console.log('Before: ', JSON.stringify(y)); 
// Before:  [[[],[],[]],[[],[],[]]]
y[0][1].push("foo");
console.log('After: ', JSON.stringify(y)); 
// After:  [[["foo"],["foo"],["foo"]],[[],[],[]]]

Why is "foo" inserted three times ? And how can I insert "foo" only in the first one i.e. How can I get

// After:  [[["foo"],[],[]],[[],[],[]]]

asked Feb 23 '19 at 18:04

Kaya Toast

5,267
8
35
59

1

you fill the array with the same object reference. – Nina Scholz Feb 23 '19 at 18:16
1

You can read here https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/fill#Description – Code Maniac Feb 23 '19 at 18:23

How to push a single value with Array.push in a two dimensional array?

0 Answers0