Home > vue-metamorph > astHelpers > findFirst

astHelpers.findFirst() function

Finds the first node in an AST that matches a partial node, using deep partial matching. This function works with both script ASTs from ESTree and template ASTs from vue-eslint-parser.

Signature:

export declare function findFirst<M extends Matcher<namedTypes.ASTNode | AST.Node>>(ast: AST.Node | namedTypes.ASTNode, matcher: M): (AST.Node & {
    type: M['type'];
}) | null;

Parameters

Parameter	Type	Description
ast	AST.Node | namedTypes.ASTNode	The node to traverse.
matcher	M	A partial object to match against. Matching uses the lodash isMatch function.

Returns:

(AST.Node & { type: M['type']; }) | null

The first matching node, or null if there's no match.

Example

// Find the first <div> in the template
const div = findFirst(sfcAST, { type: 'VElement', name: 'div' });

// Find the first console.log call in a script
const log = findFirst(scriptAST, {
  type: 'CallExpression',
  callee: {
    type: 'MemberExpression',
    object: { type: 'Identifier', name: 'console' },
    property: { type: 'Identifier', name: 'log' },
  },
});