babel/lib/6to5/transformation/transformers/validation/undeclared-variable-check.js
2015-02-11 15:57:30 +11:00

43 lines
1.0 KiB
JavaScript

"use strict";
var levenshtein = require("../../../helpers/levenshtein");
var messages = require("../../../messages");
var t = require("../../../types");
exports.optional = true;
exports.Identifier = function (node, parent, scope, file) {
if (!t.isReferenced(node, parent)) return;
if (scope.hasBinding(node.name)) return;
var msg = "Reference to undeclared variable";
// get the closest declaration to offer as a suggestion
// the variable name may have just been mistyped
var bindings = scope.getAllBindings();
var closest;
var shortest = -1;
for (var name in bindings) {
var distance = levenshtein(node.name, name);
if (distance <= 0 || distance > 3) continue;
if (distance <= shortest) continue;
closest = name;
shortest = distance;
}
var msg;
if (closest) {
msg = messages.get("undeclaredVariableSuggestion", node.name, closest);
} else {
msg = messages.get("undeclaredVariable", node.name);
}
//
throw file.errorWithNode(node, msg, ReferenceError);
};