var traverse = require("../../traverse");
var t = require("../../types");
var go = function (getBody, node, file, scope) {
var argumentsId;
var thisId;
var getArgumentsId = function () {
return argumentsId = argumentsId || t.identifier(file.generateUid("arguments", scope));
};
var getThisId = function () {
return thisId = thisId || t.identifier(file.generateUid("this", scope));
};
// traverse the function and find all alias functions so we can alias
// `arguments` and `this` if necessary
traverse(node, function (node) {
if (!node._aliasFunction) {
if (t.isFunction(node)) {
// stop traversal of this node as it'll be hit again by this transformer
return false;
} else {
return;
}
}
// traverse all child nodes of this function and find `arguments` and `this`
traverse(node, function (node, parent) {
if (t.isFunction(node) && !node._aliasFunction) {
return false;
}
if (node._ignoreAliasFunctions) return;
var getId;
if (t.isIdentifier(node) && node.name === "arguments") {
getId = getArgumentsId;
} else if (t.isThisExpression(node)) {
getId = getThisId;
} else {
return;
}
if (t.isReferenced(node, parent)) return getId();
});
return false;
});
var body;
var pushDeclaration = function (id, init) {
body = body || getBody();
body.unshift(t.variableDeclaration("var", [
t.variableDeclarator(id, init)
]));
};
if (argumentsId) {
pushDeclaration(argumentsId, t.identifier("arguments"));
}
if (thisId) {
pushDeclaration(thisId, t.identifier("this"));
}
};
exports.Program = function (node, parent, file, scope) {
go(function () {
return node.body;
}, node, file, scope);
};
exports.FunctionDeclaration =
exports.FunctionExpression = function (node, parent, file, scope) {
go(function () {
t.ensureBlock(node);
return node.body.body;
}, node, file, scope);
};
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