javascript overwrite previous element added to array

Question

When i push into my array, it overwrite the last element added.

Here is my code:

const array = [{ name: [] }];

const test = `result1
result2
result3`;
const ways = test.split(/[\n\r]+/).map(aaa => (aaa));

array.forEach((obj) => {
  ways.forEach((element) => {
    obj.item = [{ result: element }];
  });
});

The output i get :

[ 
  { 
    "name": [], 
    "item": [{ "result": "result3" }] 
  }
]

The output i want :

[
  {
    "name": [],
    "item": [
      { "result": "result1" },
      { "result": "result2" },
      { "result": "result3" }
    ]
  }
]

Some sidenotes: what is the map for? You take each value of the array that split creates and replace it with itself. And why would you want to iterate over the ways-array? You basically have an array that you want to store, as an array, in another variable. So you iterate over it and copy each value by hand. I assume you want to create a deep copy of the ways-array; I'd recommend using some built-in solution like Array.from(ways) to achieve this. — jSebestyén
– jSebestyén, Commented Mar 5, 2019 at 18:45

halfer · Accepted Answer · 2019-03-08 00:01:40Z

2

const array = [{ name: [] }];

const test = `result1
result2
result3`;
const ways = test.split(/[\n\r]+/).map(aaa => (aaa));

array.map((obj) => {
obj.item = [];
  ways.map((element) => {
    obj.item .push([{ result: element }]);
  });
});

console.log(array);

edited Mar 8, 2019 at 0:01

halfer

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answered Mar 5, 2019 at 18:30

Geeky

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Comments

ellipsis · Accepted Answer · 2019-03-05 18:29:48Z

1

You have to declare obj.item as an array and instead of equating values you should push them in the array

const array = [{
  name: []
}];

const test = `result1
result2
result3`;
const ways = test.split(/[\n\r]+/).map(aaa => (aaa));

array.forEach((obj) => {
  obj.item = [];
  ways.forEach((element) => {
    obj.item.push({
      result: element
    });
  });
});
console.log(array)

answered Mar 5, 2019 at 18:29

ellipsis

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Comments

Aziz.G · Accepted Answer · 2019-03-05 18:49:45Z

1

Using reduce method

const test = `result1
result2
result3`;

const res = test.split(/[\n\r]+/).map(aaa => (aaa)).reduce((all, acc) => {
  const [a] = all
  a.item.push({
    "result": acc
  })
  return all
}, [{
  name: [],
  item: []
}])

console.log(res)

answered Mar 5, 2019 at 18:49

Aziz.G

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