this is probably the most tricky thing to use in JavaScript and therefore TypeScript. Fortunately there is a TypeScript compiler flag noImplicit this that can help catch unsafe usages so beginners don‘t get caught off guard.
// tsconfig.json { "compilerOptions": { "noImplicitThis": true, ... }
[TypeScript] Catch unsafe use of "this" in TypeScript functions
原文：http://www.cnblogs.com/Answer1215/p/6337435.html