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This article mainly explains "what is the concept of es6 deconstruction assignment". The content of the article is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "what is the concept of es6 deconstruction assignment".

In es6, deconstructing assignment is the meaning of pattern matching for arrays or objects, and then assigning values to the variables in it; deconstructing assignment is also an extension of the assignment operator, and the syntax is "target of let deconstruction = source of deconstruction;"

This tutorial operating environment: windows10 system, ECMAScript version 6. 0, Dell G3 computer.

What does es6 deconstruct assignment mean?

Overview

Deconstructing an assignment is an extension of the assignment operator.

It is a kind of pattern matching for arrays or objects, and then assigns values to the variables in it.

The code writing is concise and easy to read, the semantics is more clear, and it also facilitates the acquisition of data fields in complex objects.

Deconstruction model

In the deconstruction, there are two parts involved:

The source of deconstruction, the right part of the assignment expression.

The goal of deconstructing the left part of the assignment expression.

Deconstruction of array model (Array)

Basic

Let [a, b, c] = [1,2,3]; / a = 1max / b = 2max / c = 3

Can be nested

Let [a, [b], c]] = [1, [2], 3]]; / a = 1max / b = 2max / c = 3

Negligible

Let [a, b] = [1,2,3]; / a = 1max / b = 3

Incomplete deconstruction

Let [a = 1, b] = []; / a = 1, b = undefined

Residual operator

Let [a,... b] = [1, 2, 3]; / / a = 1 Unimax b = [2, 3]

Examples are as follows:

Note:

The array structure on the left and right side of the assigned equal sign needs to be always, which is called "pattern matching".

If the number of variables on the left and right does not match the number of values, skip the missing part directly (remember, the one on the left is skipped, and so is the one on the right).

If there are three dots in front of a variable on the left, it means that the corresponding position on the right and all subsequent values will be combined into an array and assigned to the variable on the left, and the left must be the last variable to be preceded by three dots, otherwise an error will be reported.

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