TypeScript: How to make object from array of tuple?

Question

I have following array of tuple, need to make an object from, how?

Object.keys(invoiceItems)?.map(function (key, item) {
  [key, 1];
}

I know in Swift Dictionary(uniqueKeysWithValues: method call I need, what about in Typescript?

Does JavaScript actually have tuples (outside of this [TC39 proposal](https://github.com/tc39/proposal-record-tuple))? — jarmod, Sep 08 '21 at 17:43
@jarmod Not exactly, but TypeScript **does** have a type signature for tuples that differs from arrays (though in execution, they behave the same). — Connor Low, Sep 08 '21 at 17:44
@jarmod you have used 'let aa = Object.keys(invoiceItems).forEach((key)....' which will return undefined, try using the same with map!! — Wasit Shafi, Sep 08 '21 at 18:48
@WasitShafi no idea what you're referring to here. Nobody used `forEach` in this post. — jarmod, Sep 08 '21 at 18:53
@János /jarmod please dare to click on edited 13 min ago :) and sorry for the wrong tag!! — Wasit Shafi, Sep 08 '21 at 18:56

score 3 · Accepted Answer · answered Sep 08 '21 at 17:49

3

Assuming that by tuples you mean two-element arrays, you can use Object.fromEntries to create such object:

const entries = [
  [ "value1", 42 ],
  [ "value2", 17 ],
  [ "value3", 51 ],
];

const object = Object.fromEntries(entries);

console.log(object);

answered Sep 08 '21 at 17:49

Parzh from Ukraine

7,999
3
34
65

still a problem, would you check? https://stackoverflow.com/questions/69108183/typescipt-why-object-fromentries-does-not-accept-array-of-tuple – János Sep 08 '21 at 18:43

score 0 · Answer 2 · answered Sep 08 '21 at 19:23

Here I assume your invoice items with some dummy data, below are 2 ways to create object with key:value

const invoiceItems = [[101, 'Coffee'], [102, 'Tea'], [103, 'Book']]

// Method 1
const o =  Object.fromEntries(invoiceItems);
console.log('o :', o)


// Method 2
const o2 = {}
Object.keys(invoiceItems).forEach(i => o2[invoiceItems[i][0]] = invoiceItems[i][1])
console.log('o2 :', o2)

TypeScript: How to make object from array of tuple?

2 Answers2