2017-06-07 03:22:51 -04:00

71 lines
2.0 KiB
JavaScript

import syntaxOptionalChaining from "babel-plugin-syntax-optional-chaining";
export default function ({ types: t }) {
return {
inherits: syntaxOptionalChaining,
visitor: {
MemberExpression(path) {
if (!path.node.optional) {
return;
}
const { scope, node } = path;
const { object } = node;
node.optional = false;
const ref = scope.generateUidIdentifierBasedOnNode(object);
scope.push({ id: ref });
node.object = ref;
let parent = path;
let expression = path;
while (parent.listKey === undefined) {
expression = parent;
parent = parent.parentPath;
}
const replace = parent.isExpression() ? parent : expression;
replace.replaceWith(t.conditionalExpression(
t.binaryExpression("==", t.assignmentExpression("=", ref, object), t.nullLiteral()),
scope.buildUndefinedNode(),
replace.node
));
},
"NewExpression|CallExpression": {
exit(path) {
if (!path.node.optional) {
return;
}
const { scope, node } = path;
const { callee } = node;
node.optional = false;
const ref = scope.generateUidIdentifierBasedOnNode(callee);
scope.push({ id: ref });
node.callee = ref;
if (t.isMemberExpression(callee) && !t.isNewExpression(node)) {
const context = scope.generateUidIdentifierBasedOnNode(callee.object);
scope.push({ id: context });
callee.object = t.assignmentExpression("=", context, callee.object);
node.arguments.unshift(context);
node.callee = t.memberExpression(node.callee, t.identifier("call"));
}
path.replaceWith(t.conditionalExpression(
t.binaryExpression("==", t.assignmentExpression("=", ref, callee), t.nullLiteral()),
scope.buildUndefinedNode(),
node
));
},
},
},
};
}