Array array method of lodash commonly used api

• _.flattenDeep(array): recurse array into a one-dimensional array

  If you don't use lodash, the personal idea is to use JSON.stringify to convert the array into a string, and then use the replace method of the string to remove the characters '['and the sum. Using this method will be much more convenient']'
  

_.flattenDeep([1, [2, [3, [4]], 5]]);
// => [1, 2, 3, 4, 5]

• _.indexOf(array, value, [fromIndex=0]): returns the index value of the first value found in the array array**

  It is often used to detect whether there is a certain value in the array. If there is no such value, it will return a negative value. Example

_.indexOf([3,3], 1);//-1

Specific parameters:
array (Array): The array to be searched.
value (*): The value to look for.
[fromIndex=0] (number): The position to start the query, the default starts from 0

• _.difference(array, [values]) : filter an array according to another array

  If the array contains the values ​​in [values], then the array removes these values

  example

_.difference([1,2,3,4],[8,4]);   //[1, 2, 3]

• _.without(array, [values]): Creates a new array excluding all given values

_.without([2, 1, 2, 3], 1, 2);
// => [3]

• _.drop(array, [n=1]): remove all values ​​before the nth value in the array

_.drop([8,5,4,2,3],2) //[4, 2, 3]

• _.fill(array, value, [start=0], [end=array.length]): Use the new value to replace the value from the start position to the end position in the array

_.fill([1,2,3,4],'$',1,2) //[1, "$", 3, 4]

• .findIndex(array, [predicate= .identity], [fromIndex=0]): If the value of the array is a key-value pair, this method can be used to return the index value of the first element that is judged to be a true value by predicate (index )

var users = [
  { 'user': 'barney',  'active': false },
  { 'user': 'fred',    'active': false },
  { 'user': 'pebbles', 'active': true }
];

_.findIndex(users, function(o) { return o.user == 'barney'; });
// => 0
_.findIndex(users, ['active', false]);
// => 0

• _.head(array) : Get the first value of the array
• _.pull(array, [values]) : delete the incoming values ​​from the array

var array = [1, 2, 3, 1, 2, 3];

_.pull(array, 2, 3);
console.log(array);
// => [1, 1]

There is also a method _.pullAll(array, values), which differs from the above in that this method accepts an array of values ​​to remove.

• .remove(array, [predicate= .identity]) : remove the value in the array according to the judgment condition

var array = [1, 2, 3, 4];
var evens = _.remove(array, function(n) {
  return n % 2 == 0;
});

console.log(array);
// => [1, 3]

console.log(evens);
// => [2, 4]

• _.uniq(array): Array deduplication
• _.tail(array) : get all values ​​except the first one
• _.union([arrays]): Union of arrays

_.union([2], [1, 2]);
// => [2, 1]

• _.unzip(array): Array decomposition

var zipped = _.zip(['fred', 'barney'], [30, 40], [true, false]);
// => [['fred', 30, true], ['barney', 40, false]]

_.unzip(zipped);
// => [['fred', 'barney'], [30, 40], [true, false]]