CODEWITHSUNDEEP
javascriptarrays
user3142695
user3142695

Reputation: 17332

JS: Add/remove element from array

I want to add/remove an element to/from an array depending on an boolean value. This is what is working.

Is it possible to make this a bit shorter?

if (state === true) {
    const index = array.indexOf(id)
    if (index > -1)
        array.splice(index, 1)
}
if (state === false) {
    const index = array.indexOf(id)
    if (index === -1)
        array.push(id)
}

Upvotes: 0

Views: 399

Answers (5)

Nina Scholz
Nina Scholz

Reputation: 386604

You could use a conditional (ternary) operator ?: with checking state, depending of the function.

In the first part push only if state is falsy and in the second part splice only if state is truthy.

const index = array.indexOf(id);
index === -1 ? state || array.push(id) : state && array.splice(index, 1);

Table of truth

index  state  index === -1 ? state || array.push(id) : state && array.splice(index, 1)
-----  -----  ------------------------------------------------------------------------
   -1   true        true      true
   -1   false       true      false   array.push(id)
!==-1   true       false                                true    array.splice(index, 1)
!==-1   false      false                               false

Upvotes: 1

Craicerjack
Craicerjack

Reputation: 6332

const index = array.indexOf(id);

//condition           ? condition true         : condition false
(state && index > -1) ? array.splice(index, 1) : array.push(id);

This is using a shortened conditional operator
There is a handy list of some JavaScript Shorthands here

Upvotes: 0

RomanPerekhrest
RomanPerekhrest

Reputation: 92854

Use the following short approach:

const index = array.indexOf(id);
if (typeof state === 'boolean') {  // considering only boolean values for `state`
    (state && index > -1 && array.splice(index, 1)) || (!state && index === -1 && array.push(id));
}

Upvotes: 0

kind user
kind user

Reputation: 41893

Shortened & simplified.

const index = array.indexOf(id);

if (state === true && index > -1) {
  array.splice(index, 1)
} else if (state === false && index === -1)  {
  array.push(id)
}

Upvotes: 1

Mistalis
Mistalis

Reputation: 18279

A bit shorter:

const index = array.indexOf(id);

if (state === true && index > -1) {
    array.splice(index, 1);
} else if (state === false && index === -1) {
    array.push(id);
}

Upvotes: 1

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