Moringa JavaScript Arrays

JavaScript arrays are resizable and can contain a mix of different data types.

JavaScript arrays are not associative arrays and are zero-indexed.

Methods used to create copies i.e spread-syntax, slice(), concat(), and Array.from() methods create shallow copies of the array.

JavaScript arrays are not objects but their own primitive types.

const fruits = ['Apple', 'Banana'];

const fruits = new Array('Apple', 'Banana');

const fruits = 'Apple, Banana'.split(', ');

const fruits = [];

fruits[0]= 'Apple';

fruits[1] = 'Banana';

fruits[-1];

fruits[fruits.length - 1];

fruits[1];

fruits[0];

true

false

for (const fruit in fruits) {

console.log(fruit);

}

fruits.forEach(function(fruit, index, array) {

console.log(fruit);

});

The Array find() method returns the index of the 1st element that satisfies the provided testing function. If no values satisfy the testing function, -1 is returned.

The Array filter() method creates a new array with all elements that pass the test implemented by the provided function.

The Array reduce() method executes a callback function on each element. The final result of running the reducer across all array elements is a single value.

The Array map() method creates a new array populated with the results of calling a provided function on every element in the calling array.

['A', 'B', 'C']

[['A', 'A'], ['B', 'B'], ['C']]

[['A', 'A'], ['B', 'B'], 'C']