Record about this. $nexttick() in Vue

Herbal tea ice 2020-11-13 03:23:38
record this. nexttick vue



Problem description

Realize the idea

I understand it

Problem description

There is such a requirement in the project , There's a... In the page textArea Input box , When inputting relevant characters , for example : Underline _,#、{ When , There will be a pop-up box automatically , In the box is the input box , Let's enter the relevant content , Press enter , Relevant content will be converted and added to textArea in . The requirement is to enter the page by default textArea Get focus automatically , When you play the box , The input box in the pop-up box automatically gets the focus .

Realize the idea

Use elementUI Of el-dailog Handle as a bullet box , By monitoring extArea Input content of , Analyze whether the latest characters input meet the requirements of the pop-up box to display the pop-up box , At the same time according to different characters , The content of the input box displayed in the pop-up box is also different , At the same time let the first one in the box input Input box automatically gets focus . There is a key problem here is how to make the input state textArea Lose focus , And let the input box in the pop-up box get the verification automatically . because el-dialog The related code is written with the parent component . The solutions tried include :

(1) Let the... In the box el-input Also add autofocus=true Properties of

(2) In the corresponding box show=true When , By acquiring input Of ref,this.$ To set the capture focus

Neither of these two schemes can be tried , The first one has no effect . The second tip focus Method not defined . But in fact el-input There is a way , There will be problems in the second way , Why? ?

This is about vue About dom Asynchronous operation refresh . stay el-dialog On display ,input The input box is rendered and displayed through v-if According to the , stay dom Before normal rendering , First call focus, So I made a mistake , Finally through the following code to solve :

if ( {
this.$nextTick(() => {

I understand it

By using this.$nextTick() You can get the updated dom And operate on it , To ensure that dom There must be .

The reason for using this method is , When we modify the data of two-way binding , Data echo to dom There is a time difference , In this time difference , If directly by operation dom To get data , Can't get the latest data that has been assigned , But in nextTick Through operation dom Get it , It will be the latest .


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