What is the abstract grammar tree (AST)?

Why is it important?

Source code is only a string. To make the machine understand code logic (e. g. Babel conversion, ESLint) Check) it must be converted into a structured tree expression.

Role of the AST

AST focuses on the logical core by removing redundancy details (e.g. semicolons, brackets). It's a modern front-end tool chain (Vite). Webpack, Prettier) The cornerstone.

AST workflow

The compiler processor code usually follows the following steps:

Hyphthetic analysis : Disaggregates the string token (keywords, variables, etc.).
Syntax analysis : Token sequences are combined into AST trees according to the rules.
Convert : Walk through and modify the AST node (the core of the Babel plugin).
Code Generation : Revert the modified AST to code.

Common AST Node Type

Identifier : Identification, such as variable, function name.
Literal : Literally, e.g. string, number.
VariableDeclaration : Variable declaration.
CallExpression : Function calls.