Typescript Deep Dive by Basarat Ali Syed

TypeScript Deep Dive
Binder Error Reporting
Binding errors are added to the sourceFile's list of bindDiagnostics .
An example error detected during binding is the use of eval or arguments as a variable name in use strict scenario. The
relevant code is presented in its entirety below ( checkStrictModeEvalOrArguments is called from multiple places, call stacks
originating from bindWorker which calls different functions for different node SyntaxKind ):
function checkStrictModeEvalOrArguments(contextNode: Node, name: Node) {
if (name && name.kind === SyntaxKind.Identifier) {
let identifier = name;
if (isEvalOrArgumentsIdentifier(identifier)) {
// We check first if the name is inside class declaration or class expression; if so give explicit message
// otherwise report generic error message.
let span = getErrorSpanForNode(file, name);
file.bindDiagnostics.push(createFileDiagnostic(file, span.start, span.length,
getStrictModeEvalOrArgumentsMessage(contextNode), identifier.text));
}
}
}
function isEvalOrArgumentsIdentifier(node: Node): boolean {
return node.kind === SyntaxKind.Identifier &&
((node).text === "eval" || (node).text === "arguments");
}
function getStrictModeEvalOrArgumentsMessage(node: Node) {
// Provide specialized messages to help the user understand why we think they're in
// strict mode.
if (getContainingClass(node)) {
return Diagnostics.Invalid_use_of_0_Class_definitions_are_automatically_in_strict_mode;
}
if (file.externalModuleIndicator) {
return Diagnostics.Invalid_use_of_0_Modules_are_automatically_in_strict_mode;
}
}
return Diagnostics.Invalid_use_of_0_in_strict_mode;
Binder Error Reporting
91