Array<T>.prototype.*
concat(...items: (T | ConcatArray<T>)[]): T[]- Non-destructively concatenates 
thisand the parameters (which can be single elements or array of elements). - ES3, non-destructive
 ['a'].concat('b', ['c', 'd']) → [ 'a', 'b', 'c', 'd' ]
- Non-destructively concatenates 
 copyWithin(target: number, start: number, end?: number): this- Copies the elements whose indices range from 
startto (excl.)endto indices starting withtarget. Overlapping is handled correctly. - ES6, destructive
 ['a', 'b', 'c', 'd'].copyWithin(0, 2, 4) → [ 'c', 'd', 'c', 'd' ]
- Copies the elements whose indices range from 
 entries(): Iterable<[number, T]>- Returns an iterable over [index, element] pairs.
 - ES6, non-destructive
 Array.from(['a', 'b'].entries()) → [ [ 0, 'a' ], [ 1, 'b' ] ]
every(callback: (value: T, index: number, array: Array<T>) => boolean, thisArg?: any): boolean- Returns 
trueifcallbackreturnstruefor every element. Stops as soon as it receivesfalse. Math: ∀ - ES5, non-destructive
 [1, 2, 3].every(x => x > 0) → true[1, -2, 3].every(x => x > 0) → false
- Returns 
 fill(value: T, start?: number, end?: number): this- Assigns 
valueto every index. - ES6, destructive
 [0, 1, 2].fill('a') → [ 'a', 'a', 'a' ]
- Assigns 
 filter(callback: (value: T, index: number, array: Array<T>) => any, thisArg?: any): T[]- Returns an array with only those elements for which 
callbackreturnstrue. - ES5, non-destructive
 [1, -2, 3].filter(x => x > 0) → [ 1, 3 ]
- Returns an array with only those elements for which 
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Please, can I join you in this quest? I will do my research well on these API's and start contributing.