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Ruby Array Methods in Javascript
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/*** Custom RArray class ***/ | |
class RArray extends Array { | |
// Returns an array containing the items for which the given closure is not true. | |
reject (callback) { | |
return this.filter((val) => { | |
return !callback(val); | |
}); | |
} | |
// Returns an array containing all elements of array for which the given closure returns a true value. | |
select (callback) { | |
return this.filter(callback); | |
} | |
//Invokes the given closure once for each element of self. | |
collect (callback) { | |
return this.map(callback); | |
} | |
// Same as forEach, but passes the index of the element instead of the element itself. | |
eachIndex (callback) { | |
return this.forEach((value, index) => { | |
callback(index); | |
}); | |
} | |
// Returns true if self contains no elements. | |
empty () { | |
return this.length === 0; | |
} | |
// Returns the first element, or the first n elements, of the array. If the array is empty, the first form returns null, and the second form returns an empty array. | |
first (n) { | |
if (this.length === 0 && !n) return null; | |
return this.slice(0, n || 1); | |
} | |
// Returns the last element, or the last n elements, of the array. If the array is empty, the first form returns null, and the second form returns an empty array. | |
last (n) { | |
if (this.length === 0 && !n) return null; | |
return this.slice(-n || -1); | |
} | |
// Returns an array by removing duplicate values in self. | |
uniq () { | |
return this.filter((value, index, self) => self.indexOf(value) === index); | |
} | |
} | |
/*** Through Prototype Polution ***/ | |
// Returns an array containing the items for which the given closure is not true. | |
Array.prototype.reject = function (callback) { | |
return this.filter((val) => { | |
return !callback(val); | |
}) | |
} | |
// Returns an array containing all elements of array for which the given closure returns a true value. | |
Array.prototype.select = function (callback) { | |
return this.filter(callback); | |
} | |
//Invokes the given closure once for each element of self. | |
Array.prototype.collect = function (callback) { | |
return this.map(callback); | |
} | |
// Same as forEach, but passes the index of the element instead of the element itself. | |
Array.prototype.eachIndex = function (callback) { | |
return this.forEach((value, index) { | |
callback(index); | |
}); | |
} | |
// Returns true if self contains no elements. | |
Array.prototype.empty = function () { | |
return this.length === 0; | |
} | |
// Returns the first element, or the first n elements, of the array. If the array is empty, the first form returns null, and the second form returns an empty array. | |
Array.prototype.first = function (n) { | |
if (this.length === 0 && !n) return null; | |
return this.slice(0, n || 1); | |
} | |
// Returns the last element, or the last n elements, of the array. If the array is empty, the first form returns null, and the second form returns an empty array. | |
Array.prototype.last = function (n) { | |
if (this.length === 0 && !n) return null; | |
return this.slice(-n || -1); | |
} | |
// Returns an array by removing duplicate values in self. | |
Array.prototype.uniq = function () { | |
return this.filter((value, index, self) => self.indexOf(value) === index); | |
} |
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