For example, we have the source code:
getVersison('3.4.5') function getVersion(versionString) { const versionRegex = /(d).(d).(d+)/ const [, major, minor, patch] = versionRegex.exec(versionString) return {major, minor, patch} }
We want to transform it into:
const _versionRegex = /(d).(d).(d+)/; getVersison('3.4.5') function getVersion(versionString) { const [, major, minor, patch] = _versionRegex.exec(versionString) return {major, minor, patch} }
Babel plugin:
export default function (babel) { const { types: t } = babel; return { name: "ast-transform", // not required visitor: { RegExpLiteral(path) { const name = path.parent.id.name; //versionRege const newIdentifier = path.scope.generateUidIdentifier(name) // _versionRegex const variableDeclaration = t.variableDeclaration('const', [ t.variableDeclarator(newIdentifier, path.node) ]) // const _versionRegex = /(d).(d).(d+)/; console.log(variableDeclaration) /* - const [, major, minor, patch] = versionRegex.exec(versionString) + const [, major, minor, patch] = _versionRegex.exec(versionString) */ path.scope.rename(name, newIdentifier.name) const program = path.findParent( t.isProgram ) console.log(program.node.body) program.node.body.unshift(variableDeclaration) // + const _versionRegex = /(d).(d).(d+)/; path.parentPath.remove() // - const versionRegex = /(d).(d).(d+)/ } } }; }