Estree-to-babel NPM

Estree-to-babel

Convert ESTree-compatible JavaScript AST to Babel AST.

To use parsers like:

With babel tools like:

The thing is @babel/parser has a little differences with estree standard:

Property of ObjectExpression and ObjectPattern called ObjectProperty;
FunctionExpression of a Property located in ObjectMethod node;
File node;
StringLiteral, NumericLiteral, NullLiteral, RegExpLiteral, BooleanLiteral instead of Literal;
ClassMethod instead of MethodDefinition;
ClassPrivateMethod;
ClassPrivateName stores name as Identifier in id field;
ClassPrivateProperty instead of FieldDefinition;
OptionalMemberExpression and OptionalCallExpression instead of ChainExpression;
ImportDeclaration and ExportNamedDeclaration has attributes;
JSXText has extra field;
extra.parenthesized=true instead of ParenthesizedExpression;
etc...

Also @babel/parser has differences with typescript-estree:

ClassPrivateProperty instead of PropertyDefinition when key.type=PrivateName;
ClasseProperty instead of PropertyDefinition when key.type=Identifier;
PrivateName instead of PrivateIdentifier;
TSQualifiedName instead of MemberExpression in TSInterfaceHeritage;
TSDeclaredMethod with abstract=true instead of TSAbstractMethodDefinition;
extra.parenthesized=true instead of TSParenthesizedType;
etc...

estree-to-babel aims to smooth this differences.

Install

npm i estree-to-babel

Example

const cherow = require('cherow');
const toBabel = require('estree-to-babel');
const traverse = require('@babel/traverse').default;

const ast = toBabel(cherow.parse(`
    const f = ({a}) => a;
`));

traverse({
    ObjectProperty(path) {
        console.log(path.value.name);
        // output
        'a';
    },
});

You can provide options:

const cherow = require('cherow');
const toBabel = require('estree-to-babel');
const traverse = require('@babel/traverse').default;

const options = {
    convertParens: false,
};

const ast = toBabel(cherow.parse(`
    (a = b)
`), options);

traverse({
    AssignmentExpression(path) {
        console.log(path.parentPath.type);
        // output
        'ParenthesizedExpression';
    },
});