javascript_core_10

1. Inheritance between two existing objects: Object.setPrototypeOf (child, father);

2. Create a child object based on the existing parent object: var child=Object.create (father, {new attribute}) ;

3. Batch modify the parent objects of multiple sub-objects: before creating the first sub-object, modify the prototype of the constructor to a new object;

4. Inheritance between two types: multiple sub-types contain the same Properties and methods; ① Abstract parent type: define the same properties (methods) in the parent type constructor (prototype object); ② Borrow the parent type in the sub-type constructor: parent type constructor.apply (this, arguments) ;③ Set the subtype prototype object to inherit the parent type prototype object: Object.setPrototypeOf (subtype prototype object, parent type prototype object);

5. Judgment of the array API:

① Find the position of the specified element: indexOf/ lastIndexOf;

②Array.isArray(obj);

③Judge whether each element in the array meets the requirements: arr.every(function(val,idx,arr){return judgment condition;});④Judge whether it meets the requirements Element: arr.some(function(val,idx,arr){return judgment condition;});*(*where val: automatically obtain the current element value; idx: automatically obtain the current element position; arr: automatically obtain the current array being traversed ;return: judgment result;)

6. Traversal of array API:

① Perform the same operation on each element in the array: arr.forEach (function (val, idx, arr) { // for arr [ Modify the value of idx】);

② Based on the original array, process each element to generate a new array: arr.map (function (val, idx, arr) {//Return to the new array after modification according to val; return new value; });

7. Filter summary of array traversal:

①Copy the elements that meet the requirements in the original array to form a new array: var subArr=arr.filter (function (val, idx, arr) {return condition;});

② Summarize each element value in the array to produce a result: var r=arr.reduce(function (prev, val, idx, arr) {return the summary value of prev and val ;}, starting value); * ( * where prev is the current summary value;);

8. bind: Create a new function based on the existing function, and permanently bind this in the function to the specified object in advance;

call and apply: forcibly borrow a function, temporarily replace this in the function with the specified object (execute a function);

bind: create a new function, permanently bind this and some parameters (create a new function);