How to get values from within an array of objects?

Question

I need to get the minimum and maximum values of each of these objects within the following array. I've tried everything I know but the returned value is undefined, how can I do this? NOTE: Afterwards, I need to do the same in a constructor function and in a factory function. Is it the same procedure?

    let faixas3 = [
  {tooltip: 'de R$ 6667 até R$ 7777', minimo: 6667, maximo: 7777},
  {tooltip: 'de R$ 7778 até R$ 8889', minimo: 7778, maximo: 8889},
  {tooltip: 'de R$ 9000 até R$ 10000', minimo: 9000, maximo: 10000}
];
const {tooltip, minimo, maximo} = faixas3;
console.log({tooltip, minimo, maximo}); // { tooltip: undefined, minimo: undefined, maximo: undefined }
console.log(tooltip, minimo, maximo); // undefined undefined undefined

use [ ] not {}, const [tooltip, minimo, maximo] = faixas3;, faixas3 is an array not an object. — Rahul Sharma
– Rahul Sharma, Commented Jan 7, 2022 at 11:37
faixas3 is an array, you're using object destructuring syntax. — Teemu
– Teemu, Commented Jan 7, 2022 at 11:38
You can use .map(), the result of which will also be an array (with the values that you specified in the map callback function). Or you can use .forEach() if all you want is a "loop" that processes each item. — Peter B
– Peter B, Commented Jan 7, 2022 at 11:47
Thank you so much for your help, it was exactly what I needed to do. — Fernando Netto
– Fernando Netto, Commented Jan 7, 2022 at 11:53

Monty Tomar · Accepted Answer · 2022-01-07 11:42:19Z

1

You have an array of objects. To destructure values as you're doing in the example, you have to specify from which index you want to destructure values from.

const {tooltip, minimo, maximo} = faixas3[0];
const {tooltip, minimo, maximo} = faixas3[1];
const {tooltip, minimo, maximo} = faixas3[2];

or you can use a loop for looping over the elements.

answered Jan 7, 2022 at 11:42

Monty Tomar

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3 Comments

Teemu Over a year ago

Redeclaration of constant variables is not allowed, and overwriting an existing variable doesn't make sense in this case.

Monty Tomar Over a year ago

yes you have to use var in place of const if you wish to use all three together. I wrote all three together to tell him how he can destructure from each object of the array.

Teemu Over a year ago

You will definitely need six variables to store the values OP needs.

Ravi Tiwari · Accepted Answer · 2022-01-07 11:59:21Z

0

You can try this.

  function column(array, columnName) {
    return array.map(function(value,index) {
        return value[columnName];
    })
}  
const {tooltip, minimo, maximo} = [column(faixas3,'tooltip'),column(faixas3,'minimo'),column(faixas3,'maximo')];

answered Jan 7, 2022 at 11:59

Ravi Tiwari

1

Comments

KooiInc · Accepted Answer · 2022-01-07 13:00:11Z

You can 'redefine' faixas3 in several ways using Array.map. Here are two examples. The first map-result is used to declare variables with destructuring.

const logElem = document.querySelector(`pre`);
const faixas3 = [
  {tooltip: 'de R$ 6667 até R$ 7777', minimo: 6667, maximo: 7777},
  {tooltip: 'de R$ 7778 até R$ 8889', minimo: 7778, maximo: 8889},
  {tooltip: 'de R$ 9000 até R$ 10000', minimo: 9000, maximo: 10000}
];
const faixas_minmax1 = faixas3.map(v => [v.minimo, v.maximo]);
logElem.textContent = `faixas_minmax1: ${JSON.stringify(faixas_minmax1)}`;
const faixas_minmax2 = faixas3.map(v => ({min: v.minimo, max: v.maximo}));
logElem.textContent += `\nfaixas_minmax2: ${
  JSON.stringify(faixas_minmax2, null, 2)}`;

// destructuring assignment to variables from faixas_minmax1
const [f3min0, f3max0, f3min1, f3max1, f3min2, f3max2] = faixas_minmax1.flat();
logElem.textContent += `\nf3min0, f3max2: ${f3min0}, ${f3max2}`;

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