Update array of objects using a key variable

Question

I have an array of objects and I'm trying to update values in the array based on one of the object's keys.

I'm having difficulty storing my Key as a variable.

In this instance the object looks like so

If I'm to store my Object Key as a variable it fails and just adds the new element

    let keyDataField = 'AUDCASH';
    for (let i = this.CellRow + 1; i < this.cash2.length; i ++)
    {
      this.cash2[i].keyDataField = 0;
    };

If it's hardcoded it works

    for (let i = this.CellRow + 1; i < this.cash2.length; i++) {
      this.cash2[i].AUDCASH = 0;
    };

Any idea on how i can pass a variable please?

Just use [ ] to define the key . Replace this.cash2[i].keyDataField = 0; with this.cash2[i][keyDataField] = 0; — Deepak Dixit, May 01 '17 at 05:47

score 1 · Accepted Answer · answered May 01 '17 at 05:43

it needs to be in []

let keyDataField = 'AUDCASH';
for (let i = this.CellRow + 1; i < this.cash2.length; i ++)
{
  this.cash2[i][keyDataField] = 0;
};

see how when you are using the variable i, you can't just do cash2.i, same goes with any other variable you want to use as a key. What it is currently doing is looking for a key called keyDataField rather than what is in the keyDataField variable

score 0 · Answer 2 · answered May 01 '17 at 05:45

The first case doesn't work for you because in

let keyDataField = 'AUDCASH';
for (let i = this.CellRow + 1; i < this.cash2.length; i ++)
{
  this.cash2[i].keyDataField = 0;
};

you are trying to set the key keyDataField a value and the dot notation doesn't resolve the variable for you.

You should be using the brackets notation

this.cash2[i][keyDataField] = 0;

Update array of objects using a key variable

2 Answers2