How to convert an array of key-value tuples into an object

Question

I have an array:

[ [ 'cardType', 'iDEBIT' ],   [ 'txnAmount', '17.64' ],   [ 'txnId', '20181' ],   [ 'txnType', 'Purchase' ],   [ 'txnDate', '2015/08/13 21:50:04' ],   [ 'respCode', '0' ],   [ 'isoCode', '0' ],   [ 'authCode', '' ],   [ 'acquirerInvoice', '0' ],   [ 'message', '' ],   [ 'isComplete', 'true' ],   [ 'isTimeout', 'false' ] ] 

But I can't access data via an array's key, e.g. arr['txnId'] does not return 20181. How can I convert the above array of tuples into an object, so that I can easily access data by key.

Answer 1

As baao notes, since 2019 you can use Object.fromEntries(arr) (docs) to do exactly this on all modern browsers:

var arr = [['cardType', 'iDEBIT'],   ['txnAmount', '17.64'],   ['txnId', '20181']];  console.log(Object.fromEntries(arr));

If that’s not available, my previous solution was to map to an array of key-value objects and combine the objects by spreading into Object.assign:

Object.assign(...arr.map(([key, val]) => ({[key]: val})))