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This article mainly introduces the JavaScript virtual value caused by circular error report how to solve the relevant knowledge, the content is detailed and easy to understand, the operation is simple and fast, has a certain reference value, I believe that after reading this JavaScript false value caused circular error report how to solve the article will have a harvest, let's take a look.

I came across a scene at work today:

When the parent component passes data to the child component, when the data passed by the parent component is cycled in the child component

Sub-component error report

TypeError: Cannot read property 'menu_pid' of null at VueComponent.getTree

Later, it was found that the reason for reporting the error was during the cycle.

GetTree (list, parentId) {

Let re = new Array ()

For (let I = 0; I < list.length; iTunes +) {

Let pid = list [I] .menu _ pid; prompt to report an error here

/ / do something

}

Return re

}

It is found that there is a virtual value [{}, {}, null] in the data passed by the parent component list.

It is this imaginary value null that leads to the wrong report.

Then the code is blocked; the later code cannot be run

How to avoid such problems in the future

When the parent component passes data to the child component

Do not pass virtual values, because virtual values can lead to unexpected errors

When passing the value down; check the value

When looping at the bottom, pay attention to the robustness of the code

Remove imaginary value

Let arr = [11, 22, 33, null,', undefined]

Let newArr = []

For (let I = 0; I < arr.length; iTunes +) {

If (arr [I]) {

NewArr.push (arr [I])

}

}

Console.log (newArr); / / [11, 22, 33]

This is the end of the article on "how to solve cyclic errors caused by JavaScript imaginary values". Thank you for reading! I believe that everyone has a certain understanding of the knowledge of "how to solve the circular error caused by the false value of JavaScript". If you want to learn more knowledge, you are welcome to follow the industry information channel.

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