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Map and WeakMap Characteristics and creation of Map type To understand Map, first look at the objects. Compare the objects to learn about Map. For an object, the key in the object can only be a string!! let obj = { 1:'lihuina', "1":"lhn" } console.log(obj); //{1: "lhn"} When defining an object, although ...

1. Local disk IO - "click" to read 1.1 create FileReader object The FileReader object is used for read operations in IO operations let fd = new FileReader() 1.2 using FileReader object to read files fd.readAsArrayBuffer() reads a file asynchronously and returns ArrayBuffer fd.readAsBinaryString() reads a file asynchronously ...

Hello, we will study how to detect faces from images using conventional Javascript, HTML Canvas and OpenCV libraries. Let's look at some examples first, and then we'll continue to write code and explain If you need to view the complete code base, just get my github repositoryGitHub - rajeshpachaikani/face-detection-opencv-js: Simple demonstrati ...

This editor is extracted from the open source project: Vue JSON Schema Form The Editor section It is extracted to facilitate secondary development, use and learning Original author: Liu Jun Official website: https://vue-json-schema-form.lljj.me/ Primary directory structure: Route - route Vue route directory │ └─routes └─views └─editor Table ...

react3.0 The variable name of global import can be customized, and the specified variable name is used for on-demand import Review component value transfer: Father to son, son to father: review.js import React from "react" // When transferring values, pay attention to the problem of this pointing. There are three solutions: 1 Use bind in t ...

1, Preface: The common operation methods of strings can be summarized as add, delete, modify and query. You need to know that once a string is created, it is immutable. 2, Increase The meaning of adding is not to add content directly, but to create a copy of the string and then operate it. In addition to string splicing with + and ${}, you ...

Common Composition API setup Vue3.0 is a newly added configuration item. The value is a functionsetup is the of all composition APIsThe data and methods used in the component need to be configured in the setup functionThere are two return values of the setup function: If the return is an object, the attributes and methods in the object can ...

The company requires the implementation of complex header tables on mobile phones. The first column can be fixed and other sliding table functions. I have seen that this function is available in elementui, but its multi-level header needs to realize the object relationship between upper and lower levels, and the data returned to us by the backg ...

There are several methods of array: join() push() and pop() shift() and unshift() sort() reverse() concat() slice() splice() indexOf() and lastIndexOf() (new in ES5) forEach() (new in ES5) map() (new in ES5) filter() (newly added in ES5) every() (ES5 added) some() (new in ES5) Common array methods 1.join() join is to convert an array int ...

Chapter 5 succession Essentials of object oriented JavaScript -- Nicholas C. Zakas The syntax of class already exists in ES6 Learning how to create objects is the first step in understanding object-oriented programming. The second step is to understand inheritance. In traditional object-oriented languages, classes inherit the properties ...