Adding objects to collections elements using spread syntax

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9 Answers

spreadaddingobjects
90%

You just need to use your current state, not INITIAL_STATE, as the base of your object.,Please be sure to answer the question. Provide details and share your research!,Find centralized, trusted content and collaborate around the technologies you use most.

You just need to use your current state, not INITIAL_STATE, as the base of your object.

return {
   ...state,
   collection: {
      ...state.collection,
      ...action.payload
   }
};
const state = {
   name: 1,
   collection: {
      test3: {
         a: 3
      },
      test4: {
         a: 4
      }
   }
};
const payload = {
   test5: {
      a: 5
   }
};

console.log({
   ...state,
   collection: {
      ...state.collection,
      ...payload
   }
});
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88%

Spread syntax can be used when all elements from an object or array need to be included in a list of some kind. , To use new with an array of parameters without spread syntax, you would have to do it indirectly through partial application: ,With spread syntax the above can be written as:

function sum(x, y, z, n) {
   return x + y + z + n;
}
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72%

For example, the push() method of an array object allows you to add one or more elements to an array. If you want to pass an array to the push() method, you need to use apply() method as follows:,Sometimes, a function may accept an indefinite number of arguments. Filling arguments from an array is not convenient.,ES6 provides a new operator called spread operator that consists of three dots (...). The spread operator allows you to spread out elements of an iterable object such as an array,a  map, or a set. For example:

ES6 provides a new operator called spread operator that consists of three dots (...). The spread operator allows you to spread out elements of an iterable object such as an array,a  map, or a set. For example:

.wp - block - code {
      border: 0;
      padding: 0;
   }

   .wp - block - code > div {
      overflow: auto;
   }

   .shcb - language {
      border: 0;
      clip: rect(1 px, 1 px, 1 px, 1 px); -
      webkit - clip - path: inset(50 % );
      clip - path: inset(50 % );
      height: 1 px;
      margin: -1 px;
      overflow: hidden;
      padding: 0;
      position: absolute;
      width: 1 px;
      word - wrap: normal;
      word - break: normal;
   }

   .hljs {
      box - sizing: border - box;
   }

   .hljs.shcb - code - table {
      display: table;
      width: 100 % ;
   }

   .hljs.shcb - code - table > .shcb - loc {
      color: inherit;
      display: table - row;
      width: 100 % ;
   }

   .hljs.shcb - code - table.shcb - loc > span {
      display: table - cell;
   }

   .wp - block - code code.hljs: not(.shcb - wrap - lines) {
      white - space: pre;
   }

   .wp - block - code code.hljs.shcb - wrap - lines {
      white - space: pre - wrap;
   }

   .hljs.shcb - line - numbers {
      border - spacing: 0;
      counter - reset: line;
   }

   .hljs.shcb - line - numbers > .shcb - loc {
      counter - increment: line;
   }

   .hljs.shcb - line - numbers.shcb - loc > span {
      padding - left: 0.75 em;
   }

   .hljs.shcb - line - numbers.shcb - loc::before {
      border - right: 1 px solid #ddd;
      content: counter(line);
      display: table - cell;
      padding: 0 0.75 em;
      text - align: right; -
      webkit - user - select: none; -
      moz - user - select: none; -
      ms - user - select: none;
      user - select: none;
      white - space: nowrap;
      width: 1 % ;
   }
const odd = [1, 3, 5];
const combined = [2, 4, 6, ...odd];
console.log(combined);
Code language: JavaScript(javascript)
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65%

In JavaScript, objects are used to store multiple values as a complex data structure.,Map is a collection of key-value pairs where the key can be of any type. Map remembers the original order in which the elements were added to it, which means data can be retrieved in the same order it was inserted in.,Which returns a Map with three elements:

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75%

6 Use Case of Spread with Array in JavaScript ,Here are 6 ways to use the Spread operator with Array in JavaScript. You can use it to merge or clone an array. Or use it to convert iterables to an array., 5 Way to Append Item to Array in JavaScript

// Merge Array
[...array1, ...array2]

// Clone Array
[...array]

// String → Array
[...'string']

// Set  → Array
[...new Set([1, 2, 3])]

// Node List → Array
[...nodeList]

// Arguments → Array
[...arguments]
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40%

Javascript’s recently added spread syntax is a good case in point.,Using spread clones enumerable properties from a provided object literal onto a new object.,The for…in loop syntax can also be used on object literals, to iterate over its enumerable properties (which are the key-value pairs). This loop includes inherited properties from prototype chain.

For example, an array:

const arr = [‘a’, ‘b’, ‘c’];
for (const x of arr) { // here's the for..of statement  console.log(x);}
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22%

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 Pretag team - issue, fix, solve, resolve
60%

Adding an element to a map can be done either using the put method, the subscript operator or using putAll:,2.4.1. Adding or removing elements,1.4.2. Adding or removing elements

def list = [5, 6, 7, 8]
assert list.get(2) == 7
assert list[2] == 7
assert list instanceof java.util.List

def emptyList = []
assert emptyList.size() == 0
emptyList.add(5)
assert emptyList.size() == 1
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48%

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