A brief analysis of life cycle and data sharing in Vue

This article will take you to continue learningVue, and introduce in detail the life cycle and data sharing in the essential knowledge for getting started with Vue. I hope it will be helpful to everyone!

1. Component life cycle

##1.1 Life cycle & life cycle function

1️⃣ Life Cycle refers to the entire stage of a component from

creation → running → destruction , emphasizes a time period . (Learning video sharing: vue video tutorial)

2️⃣ Life cycle function: It is a

built-in function provided by the vue framework, which will accompany the life cycle of the component, Automatically execute in order.

? Warm reminder?:

Life cycle emphasizes time period, lifecycle function emphasizes time point.

1.2 Classification of component life cycle functions

1.3 Life cycle diagram Indication

You can refer to the "life cycle diagram" given in vue official documentation to further understand the process of component life cycle execution:

https://cn.vuejs.org/ v2/guide/instance.html#Life cycle diagram

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2. Data sharing between components

2.1 Relationship between components

In project development, the most common relationships between components are divided into the following two types:

• Father-son relationship

• Brother relationship

2.2 Data sharing between parent and child components

Data sharing between parent and child components is divided into:

• Parent → Child Shared data

• Child → ParentShared data

2.2.1 Parent component to child Components share data

To share data from a parent component to a child component, you need to use

custom attributes. The sample code is as follows:

2.2.2 Child component shares data with parent component

Uses when child component shares data with parent component

Custom events. The sample code is as follows:

2.3 Data sharing between sibling components

In vue2.x, sibling components The data sharing scheme between them is

EventBus.
?Steps for using EventBus?:

Create the
1. eventBus.js module and share a Vue instance object externally;
On the data sender, call the
2. bus.$emit('event name', data to be sent) method to trigger the custom event;
On the data receiver, call
3. bus.$on('Event name', event handling function) method registers a custom event;

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3. ref reference

3.1 What is ref reference

1️⃣ ref is used to assist developers to obtain DOM without

not relying on jQuery. A reference to an element or component. 2️⃣ Each vue component instance contains a

$refs object

, which stores references to the corresponding DOM elements or components. By default, component's $refs point to an empty object . The code demonstration is as follows:

3.2 Use ref to reference the DOM elementIf you want to use If ref refers to a DOM element on the page, it can be operated as follows:

The code is demonstrated as follows:

##3.3 Use ref to reference component instances

If you want to use

ref To reference the component instance on the page, you can operate as follows:

3.4 Control the on-demand switching of text boxes and buttons

Use Boolean value

inputVisible to control the on-demand switching of the text box and button in the component. The sample code is as follows:

3.5 Let the text box automatically gain focus

After the text box is displayed, if you want If it gets focus immediately, you can add a ref reference to it and call the

.focus() method of the native DOM object. The sample code is as follows:

##3.6 this.$nextTick(cb) method

$nextTick of the component The (cb)

method will defer the cb callback to execution after the next DOM update cycle. The popular understanding is: wait for the DOM update of the component to be completed before executing the cb callback function. This ensures that the cb callback function can operate on the latest DOM elements.
(Learning video sharing:

web front-end development

, Basic programming video)

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