Estree-to-babel

Convert ESTree-compatible JavaScript AST to Babel AST.

To use parsers like:

• acorn
• cherow
• espree
• etc...

With babel tools like:

• @babel/traverse
• @babel/types
• etc...

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:

import * as cherow from 'cherow';
import {estreeToBabel} from 'estree-to-babel';
import traverse from '@babel/traverse';

const options = {
    convertParens: false,
};

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

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

License

MIT