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/**
* Copyright (c) Meta Platforms, Inc. and affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
*
* @format
*/
"use strict";
const traverse = require("@babel/traverse").default;
const nullthrows = require("nullthrows");
function normalizePseudoglobals(ast, options) {
var _options$reservedName;
const reservedNames = new Set(
(_options$reservedName =
options === null || options === void 0
? void 0
: options.reservedNames) !== null && _options$reservedName !== void 0
? _options$reservedName
: []
);
const renamedParamNames = [];
traverse(ast, {
Program(path) {
const params = path.get("body.0.expression.arguments.0.params");
const body = path.get("body.0.expression.arguments.0.body");
if (!body || Array.isArray(body) || !Array.isArray(params)) {
path.stop();
return;
}
const pseudoglobals = params // $FlowFixMe Flow error uncovered by typing Babel more strictly
.map((path) => path.node.name)
.filter((name) => !reservedNames.has(name));
const usedShortNames = new Set();
const namePairs = pseudoglobals.map((fullName) => [
fullName,
getShortName(fullName, usedShortNames),
]);
for (const [fullName, shortName] of namePairs) {
if (reservedNames.has(shortName)) {
throw new ReferenceError(
"Could not reserve the identifier " +
shortName +
" because it is the short name for " +
fullName
);
}
renamedParamNames.push(rename(fullName, shortName, body.scope));
}
path.stop();
},
});
return renamedParamNames;
}
function getShortName(fullName, usedNames) {
// Try finding letters that are semantically relatable to the name
// of the variable given. For instance, in XMLHttpRequest, it will
// first match "X", then "H", then "R".
const regexp = /^[^A-Za-z]*([A-Za-z])|([A-Z])[a-z]|([A-Z])[A-Z]+$/g;
let match;
while ((match = regexp.exec(fullName))) {
const name = (match[1] || match[2] || match[3] || "").toLowerCase();
if (!name) {
throw new ReferenceError(
"Could not identify any valid name for " + fullName
);
}
if (!usedNames.has(name)) {
usedNames.add(name);
return name;
}
}
throw new ReferenceError(
`Unable to determine short name for ${fullName}. The variables are not unique: ${Array.from(
usedNames
).join(", ")}`
);
}
function rename(fullName, shortName, scope) {
let unusedName = shortName; // `generateUid` generates a name of the form name_ even if there was no conflict which we don't want.
// Check if the desired name was never used and in that case proceed and only use `generateUid` if there's a
// name clash.
if (
scope.hasLabel(shortName) ||
scope.hasBinding(shortName) ||
scope.hasGlobal(shortName) ||
scope.hasReference(shortName)
) {
unusedName = scope.generateUid(shortName);
const programScope = scope.getProgramParent();
nullthrows(programScope.references)[shortName] = true;
nullthrows(programScope.uids)[shortName] = true;
}
scope.rename(fullName, unusedName);
return unusedName;
}
module.exports = normalizePseudoglobals;