const node = path.node;
if (t.isIdentifier(node) && node.name === "n") {
node.name = "x";
}
}
});
// Examples from https://github.com/thejameskyle/babel-handbook/blob/master/translations/en/plugin-handbook.md#writing-your-first-babel-plugin
const v1: Visitor = {
BinaryExpression(path) {
if (t.isIdentifier(path.node.left)) {
// ...
}
path.replaceWith(
t.binaryExpression("**", path.node.left, t.numericLiteral(2))
);
path.parentPath.replaceWith(
t.expressionStatement(t.stringLiteral("Anyway the wind blows, doesn't really matter to me, to me."))
);
path.parentPath.remove();
},
Identifier(path) {
if (path.isReferencedIdentifier()) {
// ...
}
if (t.isQualifiedTypeIdentifier(path.node, path.parent)) {
// ...
}
},
function plugin(babel) {
const { types: t } = babel;
function handleFunction(path) {
const declarators: any[] = [];
path.node.params.forEach((param, i) => {
if (param.type === "ObjectPattern") {
// do nothing for now, logic is in objectpattern visitor
// for (var n = 0; n < param.properties.length; n++) {
// const prop = param.properties[n];
// declarators.push(
// t.variableDeclarator(
// addLoc(
// getTrackingIdentifier(
// prop.value ? prop.value.name : prop.key.name
// ),
// prop.loc
// ),
// t.nullLiteral()
// )
// );
// }
} else if (param.type === "ArrayPattern") {
param.elements.forEach(elem => {
let varName;
if (elem.type === "Identifier") {
varName = elem.name;
} else if (elem.type === "AssignmentPattern") {
varName = elem.left.name;
} else if (elem.type === "RestParameter") {
varName = elem.argument.name;
} else if (elem.type === "ObjectPattern") {
// will be processed in ObjectPattern visitor
} else {
throw Error("aaa unknown array pattern elem type " + elem.type);
}
declarators.push(
t.variableDeclarator(
addLoc(getTrackingIdentifier(varName), param.loc),
ignoredCallExpression(FunctionNames.getEmptyTrackingInfo, [
ignoredStringLiteral("arrayPatternInFunction"),
getLocObjectASTNode(elem.loc)
])
)
);
});
} else if (param.type === "AssignmentPattern") {
let varName = param.left.name;
declarators.push(
t.variableDeclarator(
addLoc(getTrackingIdentifier(varName), param.loc),
ignoredCallExpression(FunctionNames.getEmptyTrackingInfo, [
ignoredStringLiteral("arrayPatternInFunction"),
getLocObjectASTNode(param.loc)
])
)
);
} else if (param.type === "RestElement") {
let varName = param.argument.name;
declarators.push(
t.variableDeclarator(
addLoc(getTrackingIdentifier(varName), param.loc),
ignoredCallExpression(FunctionNames.getEmptyTrackingInfo, [
ignoredStringLiteral("restElement"),
getLocObjectASTNode(param.loc)
])
)
);
} else {
declarators.push(
t.variableDeclarator(
addLoc(getTrackingIdentifier(param.name), param.loc),
t.callExpression(
t.identifier(FunctionNames.getFunctionArgTrackingInfo),
[t.numericLiteral(i)]
)
)
);
}
});
// keep whole list in case the function uses `arguments` object
// We can't just access the arg tracking values when `arguments` is used (instead of doing it
// at the top of the function)
// That's because when we return the argTrackingValues are not reset to the parent function's
declarators.push(
t.variableDeclarator(
ignoredIdentifier("__allArgTV"),
ignoredCallExpression(FunctionNames.getFunctionArgTrackingInfo, [])
)
);
const d = t.variableDeclaration("var", declarators);
skipPath(d);
if (path.node.body.type !== "BlockStatement") {
// arrow function
path.node.body = ignoreNode(
t.blockStatement([ignoreNode(t.returnStatement(path.node.body))])
);
}
path.node.body.body.unshift(d);
path.node.ignore = true; // I'm not sure why it would re-enter the functiondecl/expr, but it has happened before
}
const visitors = {
FunctionDeclaration(path) {
handleFunction(path);
},
FunctionExpression(path) {
handleFunction(path);
},
ArrowFunctionExpression(path) {
handleFunction(path);
},
ClassMethod(path) {
handleFunction(path);
},
ObjectPattern(path) {
// debugger;
const newProperties: any[] = [];
path.node.properties.forEach(prop => {
let varName;
if (prop.value && prop.value.type === "Identifier") {
varName = prop.value.name;
} else if (prop.value && prop.value.type === "AssignmentPattern") {
varName = prop.value.left.name;
} else if (prop.type === "RestElement") {
varName = prop.argument.name;
} else {
varName = prop.key.name;
}
newProperties.push(
skipPath(
t.ObjectProperty(
ignoreNode(getTrackingIdentifier(varName)),
t.assignmentPattern(
getTrackingIdentifier(varName),
ignoredCallExpression(FunctionNames.getEmptyTrackingInfo, [
ignoredStringLiteral("objectPattern"),
getLocObjectASTNode(prop.loc)
])
)
)
)
);
newProperties.push(prop);
});
path.node.properties = newProperties;
},
ForOfStatement(path) {
if (path.node.left.type === "VariableDeclaration") {
const variableDeclarator = path.node.left.declarations[0];
let varKind = "let";
if (path.node.left.kind === "var") {
// should leak into parent scope
varKind = "var";
}
if (variableDeclarator.id.type === "Identifier") {
if (!path.node.body.body) {
path.node.body = ignoreNode(
babel.types.blockStatement([path.node.body])
);
}
path.node.body.body.unshift(
skipPath(
t.variableDeclaration(varKind, [
t.variableDeclarator(
ignoredIdentifier(
getTrackingVarName(variableDeclarator.id.name)
),
ignoredCallExpression(FunctionNames.getEmptyTrackingInfo, [
ignoredStringLiteral("forOfVariable"),
getLocObjectASTNode(variableDeclarator.loc)
])
)
])
)
);
}
}
},
VariableDeclaration(path) {
if (["ForInStatement", "ForOfStatement"].includes(path.parent.type)) {
return;
}
var originalDeclarations = path.node.declarations;
var newDeclarations: any[] = [];
originalDeclarations.forEach(function(decl) {
newDeclarations.push(decl);
if (!decl.init) {
decl.init = addLoc(ignoredIdentifier("undefined"), decl.loc);
}
if (decl.id.type === "ArrayPattern") {
// declaration are inserted into pattern already
} else if (decl.id.type === "ObjectPattern") {
// declarations are inserted into object pattern already
} else {
newDeclarations.push(
t.variableDeclarator(
addLoc(getTrackingIdentifier(decl.id.name), decl.id.loc),
skipPath(
t.callExpression(
t.identifier(FunctionNames.getLastOperationTrackingResult),
[]
)
)
)
);
}
});
path.node.declarations = newDeclarations;
},
WithStatement(path) {
function i(node) {
if (node.name === null) {
debugger;
}
node.ignoreInWithStatementVisitor = true;
return node;
}
// not an ideal way to track things and might not work for nested
// with statements, but with statement use should be rare.
// Underscore uses them for templates though.
let obj = path.node.object;
path.get("object").traverse({
Identifier(path) {
path.replaceWith(i(path.node));
}
});
path.traverse({
Identifier(path) {
if (path.node.ignoreInWithStatementVisitor) {
return;
}
if (shouldSkipIdentifier(path)) {
return;
}
if (
["WithStatement", "FunctionExpression"].includes(path.parent.type)
) {
return;
}
if (path.parent.type === "MemberExpression") {
if ((path.parent.property = path.node)) {
console.log("ignoreing");
return;
}
}
path.node.ignoreInWithStatementVisitor = true;
const identifierName = path.node.name;
path.replaceWith(
ignoreNode(
t.conditionalExpression(
ignoreNode(
t.binaryExpression(
"in",
addLoc(t.stringLiteral(identifierName), path.node.loc),
obj
)
),
addLoc(
t.memberExpression(
obj,
addLoc(t.stringLiteral(identifierName), path.node.loc),
true
),
path.node.loc
),
i(addLoc(t.identifier(identifierName), path.node.loc))
)
)
);
}
});
},
CatchClause(path) {
const errName = path.node.param.name;
// We don't track anything, but this var has to exist to avoid "err___tv is undeclared" errors
const trackingVarDec = skipPath(
t.variableDeclaration("let", [
t.variableDeclarator(t.identifier(getTrackingVarName(errName)))
])
);
path.node.body.body.unshift(trackingVarDec);
},
ArrayPattern(path) {
const isForOfStatementWithVarDeclaration =
path.parentPath.node.type === "VariableDeclarator" &&
path.parentPath.parentPath.parentPath.node.type === "ForOfStatement";
const isForOfStatementWithoutVarDeclaration =
path.parentPath.node.type === "ForOfStatement";
const namedParamCount = path.node.elements.filter(
el => el.type !== "RestElement"
).length;
if (
isForOfStatementWithVarDeclaration ||
isForOfStatementWithoutVarDeclaration
) {
let forOfStatement;
if (isForOfStatementWithVarDeclaration) {
forOfStatement = path.parentPath.parentPath.parentPath.node;
} else if (isForOfStatementWithoutVarDeclaration) {
forOfStatement = path.parentPath.node;
}
forOfStatement.right = ignoredCallExpression(
FunctionNames.expandArrayForArrayPattern,
[
forOfStatement.right,
getLocObjectASTNode(forOfStatement.loc),
ignoredStringLiteral("forOf"),
ignoredNumericLiteral(namedParamCount)
]
);
} else if (
path.parentPath.parentPath.node.type === "VariableDeclaration"
) {
const declarator = path.parentPath.node;
declarator.init = ignoredCallExpression(
FunctionNames.expandArrayForArrayPattern,
[
declarator.init,
getLocObjectASTNode(declarator.loc),
ignoredStringLiteral("variableDeclarationInit"),
ignoredNumericLiteral(namedParamCount)
]
);
} else if (path.parentPath.node.type === "AssignmentExpression") {
const assignmentExpression = path.parentPath.node;
assignmentExpression.right = ignoredCallExpression(
FunctionNames.expandArrayForArrayPattern,
[
assignmentExpression.right,
getLocObjectASTNode(assignmentExpression.loc),
ignoredStringLiteral("assignmentExpressionRight"),
ignoredNumericLiteral(namedParamCount)
]
);
}
const arrayPattern = path.node;
const newElements: any[] = [];
arrayPattern.elements.forEach(elem => {
let varName;
if (elem.type === "Identifier") {
varName = elem.name;
} else if (elem.type === "AssignmentPattern") {
varName = elem.left.name;
} else if (elem.type === "RestElement") {
varName = elem.argument.name;
} else if (elem.type === "ObjectPattern") {
// will be processed in ObjectPattern visitor
} else {
throw Error("array pattern elem type " + elem.type);
}
if (elem.type !== "RestElement") {
newElements.push(elem);
newElements.push(addLoc(getTrackingIdentifier(varName), elem.loc));
} else {
// Rest element must be last element
newElements.push(addLoc(getTrackingIdentifier(varName), elem.loc));
newElements.push(elem);
}
// newDeclarations.push(
// t.variableDeclarator(
// ,
// skipPath(
// ignoredCallExpression(FunctionNames.getEmptyTrackingInfo, [
// ignoredStringLiteral("arrayPatternInVarDeclaration"),
// getLocObjectASTNode(elem.loc)
// ])
// )
// )
// );
});
arrayPattern.elements = newElements;
},
ForInStatement(path) {
let varName;
let isNewVariable;
let varKind = "let";
if (path.node.left.type === "VariableDeclaration") {
const variableDeclaration = path.node.left;
varName = variableDeclaration.declarations[0].id.name;
if (variableDeclaration.kind === "var") {
// should leak into outer scope
varKind = "var";
}
isNewVariable = true;
} else if (path.node.left.type === "Identifier") {
varName = path.node.left.name;
isNewVariable = false;
} else {
throw Error("not sure what this is");
}
if (path.node.body.type !== "BlockStatement") {
// Technically it might not be safe to make this conversion
// because it affects scoping for let/const inside the body
// ...although that's not usually what you do inside a for in body
path.node.body = ignoreNode(
babel.types.blockStatement([path.node.body])
);
}
const body = path.node.body.body;
let forInRightValueIdentifier = ignoreNode(
path.scope.generateUidIdentifier("__forInRightVal")
);
// insertBefore causes this ForInStatement to be visited again
// if a block body is introduced for the parent (e.g. if the parent
// was a single-statement if statement before)
// Prevent processing this ForInStatement twice
path.node.ignore = true;
path.insertBefore(
ignoreNode(
t.variableDeclaration("let", [
t.variableDeclarator(forInRightValueIdentifier, path.node.right)
])
)
);
path.node.right = forInRightValueIdentifier;
var assignment = ignoreNode(
t.expressionStatement(
ignoreNode(
t.assignmentExpression(
"=",
ignoredIdentifier(getTrackingVarName(varName)),
ignoredCallExpression(
FunctionNames.getObjectPropertyNameTrackingValue,
[forInRightValueIdentifier, ignoredIdentifier(varName)]
)
)
)
)
);
body.unshift(assignment);
if (isNewVariable) {
var declaration = ignoreNode(
// Note: this needs to be let or else there could be conflict with
// a var from parent scope
t.variableDeclaration(varKind, [
t.variableDeclarator(ignoredIdentifier(getTrackingVarName(varName)))
])
);
body.unshift(declaration);
}
}
};
Object.keys(operations).forEach(key => {
var operation = operations[key];
key = key[0].toUpperCase() + key.slice(1);
if (operation.visitor) {
if (visitors[key]) {
throw Error("duplicate visitor " + key);
}
visitors[key] = path => {
var ret = operation.visitor.call(operation, path);
if (ret) {
if (!ret.loc) {
// debugger;
}
try {
path.replaceWith(ret);
} catch (err) {
// for easier debugging
debugger;
operation.visitor.call(operation, path);
throw err;
}
}
};
}
});
// var enter = 0;
// var enterNotIgnored = 0;
Object.keys(visitors).forEach(key => {
var originalVisitor = visitors[key];
visitors[key] = function(path) {
// enter++;
if (path.node.skipPath) {
path.skip();
return;
}
if (path.node.skipKeys) {
path.skipKeys = path.node.skipKeys;
return;
}
if (path.node.ignore) {
return;
}
// enterNotIgnored++;
return originalVisitor.apply(this, arguments);
};
});
visitors["Program"] = {
// Run on exit so injected code isn't processed by other babel plugins
exit: function(path) {
const babelPluginOptions = plugin["babelPluginOptions"];
let usableHelperCode;
if (babelPluginOptions) {
const { accessToken, backendPort } = babelPluginOptions;
usableHelperCode = helperCode;
usableHelperCode = usableHelperCode.replace(
/ACCESS_TOKEN_PLACEHOLDER/g,
accessToken
);
usableHelperCode = usableHelperCode.replace(
/BACKEND_PORT_PLACEHOLDER/g,
backendPort
);
} else {
usableHelperCode = helperCode;
}
// console.log({ enter, enterNotIgnored });
var initCodeAstNodes = babylon
.parse(usableHelperCode)
.program.body.reverse();
initCodeAstNodes.forEach(node => {
path.node.body.unshift(node);
});
}
};
return {
name: "fromjs-babel-plugin",
visitor: visitors
};
}