diff --git a/README.md b/README.md index d13f3ba..9287711 100644 --- a/README.md +++ b/README.md @@ -31,8 +31,8 @@ Feel free to browse each cheatsheet to learn new things and to keep them at hand
JavaScript -* [Arrays](languages/javascript/arrays.js) * [Objects](languages/javascript/objects.js) +* [Arrays](languages/javascript/arrays.js)
@@ -116,7 +116,7 @@ You are more than welcome to contribute and build your own cheatsheet for your f - + diff --git a/languages/javascript/objects.js b/languages/javascript/objects.js index fa7a5e2..eb9e388 100644 --- a/languages/javascript/objects.js +++ b/languages/javascript/objects.js @@ -1,52 +1,44 @@ /* ******************************************************************************************* - * GLOBAL OBJECTS > ARRAY - * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array + * GLOBAL OBJECTS > OBJECT + * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object * ******************************************************************************************* */ - // Global object: properties -Array.length // Reflects the number of elements in an array. -Array.prototype // Represents the prototype for the Array constructor and allows to add new properties and methods to all Array objects. +Object.length // length is a property of a function object, and indicates how many arguments the function expects, i.e. the number of formal parameters. This number does not include the rest parameter. Has a value of 1. +Object.prototype // Represents the Object prototype object and allows to add new properties and methods to all objects of type Object. -// Global object: methods -Array.from(arrayLike[, mapFn[, thisArg]]) // Creates a new Array instance from an array-like or iterable object. -Array.isArray(obj) // Returns true if a variable is an array, if not false. -Array.of(element0[, element1[, ...[, elementN]]]) // Creates a new Array instance with a variable number of arguments, regardless of number or type of the arguments. +// Methods of the Object constructor +Object.assign(target, ...sources) // Copies the values of all enumerable own properties from one or more source objects to a target object. method is used to copy the values of all enumerable own properties from one or more source objects to a target object. It will return the target object +Object.create(MyObject) // Creates a new object with the specified prototype object and properties. The object which should be the prototype of the newly-created object. +Object.defineProperty(obj, prop, descriptor) // Adds the named property described by a given descriptor to an object. +Object.defineProperties(obj, props) // Adds the named properties described by the given descriptors to an object. +Object.entries(obj) // Returns an array containing all of the [key, value] pairs of a given object's own enumerable string properties. +Object.freeze(obj) // Freezes an object: other code can't delete or change any properties. +Object.getOwnPropertyDescriptor(obj, prop) // Returns a property descriptor for a named property on an object. +Object.getOwnPropertyDescriptors(obj) // Returns an object containing all own property descriptors for an object. +Object.getOwnPropertyNames(obj) // Returns an array containing the names of all of the given object's own enumerable and non-enumerable properties. +Object.getOwnPropertySymbols(obj) // Returns an array of all symbol properties found directly upon a given object. +Object.getPrototypeOf(obj) // Returns the prototype of the specified object. +Object.is(value1, value2); // Compares if two values are the same value. Equates all NaN values (which differs from both Abstract Equality Comparison and Strict Equality Comparison). +Object.isExtensible(obj) // Determines if extending of an object is allowed. +Object.isFrozen(obj) // Determines if an object was frozen. +Object.isSealed(obj) // Determines if an object is sealed. +Object.keys(obj) // Returns an array containing the names of all of the given object's own enumerable string properties. +Object.preventExtensions(obj) // Prevents any extensions of an object. +Object.seal(obj) // Prevents other code from deleting properties of an object. +Object.setPrototypeOf(obj, prototype) // Sets the prototype (i.e., the internal [[Prototype]] property). +Object.values(obj) // Returns an array containing the values that correspond to all of a given object's own enumerable string properties. -// Instance: properties -arr.length // Reflects the number of elements in an array. +// Object instances and Object prototype object (Object.prototype.property or Object.prototype.method()) +// Properties +obj.constructor // Specifies the function that creates an object's prototype. +obj.__proto__ // Points to the object which was used as prototype when the object was instantiated. -// Instance: mutator methods -arr.copyWithin(target, start, end) // Copies a sequence of array elements within the array. -arr.fill(value, start, end) // Fills all the elements of an array from a start index to an end index with a static value. -arr.pop() // Removes the last element from an array and returns that element. -arr.push([element1[, ...[, elementN]]]) // Adds one or more elements to the end of an array and returns the new length of the array. -arr.reverse() // Reverses the order of the elements of an array in place — the first becomes the last, and the last becomes the first. -arr.shift() // Removes the first element from an array and returns that element. -arr.sort() // Sorts the elements of an array in place and returns the array. -array.splice(start, deleteCount, item1, item2, ...) // Adds and/or removes elements from an array. -arr.unshift([element1[, ...[, elementN]]]) // Adds one or more elements to the front of an array and returns the new length of the array. +// Methods +obj.hasOwnProperty(prop) // Returns a boolean indicating whether an object contains the specified property as a direct property of that object and not inherited through the prototype chain. +prototypeObj.isPrototypeOf(object) // Returns a boolean indicating whether the object this method is called upon is in the prototype chain of the specified object. +obj.propertyIsEnumerable(prop) // Returns a boolean indicating if the internal ECMAScript [[Enumerable]] attribute is set. +obj.toLocaleString() // Calls toString(). +obj.toString() // Returns a string representation of the object. +object.valueOf() // Returns the primitive value of the specified object. -// Instance: accessor methods -arr.concat(value1[, value2[, ...[, valueN]]]) // Returns a new array comprised of this array joined with other array(s) and/or value(s). -arr.includes(searchElement, fromIndex) // Determines whether an array contains a certain element, returning true or false as appropriate. -arr.indexOf(searchElement[, fromIndex]) // Returns the first (least) index of an element within the array equal to the specified value, or -1 if none is found. -arr.join(separator) // Joins all elements of an array into a string. -arr.lastIndexOf(searchElement, fromIndex) // Returns the last (greatest) index of an element within the array equal to the specified value, or -1 if none is found. -arr.slice(begin, end) // Extracts a section of an array and returns a new array. -arr.toString() // Returns a string representing the array and its elements. Overrides the Object.prototype.toString() method. -arr.toLocaleString(locales, options) // Returns a localized string representing the array and its elements. Overrides the Object.prototype.toLocaleString() method. - -// Instance: iteration methods -arr.entries() // Returns a new Array Iterator object that contains the key/value pairs for each index in the array. -arr.every(callback[, thisArg]) // Returns true if every element in this array satisfies the provided testing function. -arr.filter(callback[, thisArg]) // Creates a new array with all of the elements of this array for which the provided filtering function returns true. -arr.find(callback[, thisArg]) // Returns the found value in the array, if an element in the array satisfies the provided testing function or undefined if not found. -arr.findIndex(callback[, thisArg]) // Returns the found index in the array, if an element in the array satisfies the provided testing function or -1 if not found. -arr.forEach(callback[, thisArg]) // Calls a function for each element in the array. -arr.keys() // Returns a new Array Iterator that contains the keys for each index in the array. -arr.map(callback[, initialValue]) // Creates a new array with the results of calling a provided function on every element in this array. -arr.reduce(callback[, initialValue]) // Apply a function against an accumulator and each value of the array (from left-to-right) as to reduce it to a single value. -arr.reduceRight(callback[, initialValue]) // Apply a function against an accumulator and each value of the array (from right-to-left) as to reduce it to a single value. -arr.some(callback[, initialValue]) // Returns true if at least one element in this array satisfies the provided testing function. -arr.values() // Returns a new Array Iterator object that contains the values for each index in the array.