Jul 20, 2019 · In JavaScript, it's commonly seen as best practice to use === instead of ==, for obvious and well-known reasons. In TypeScript, which is one to be preferred? Is there even …

Feb 2, 2019 · Alternatively, you can type name1 as string | undefined, and handle cases of undefined further down. However, it's typically better to handle unexpected errors earlier on. …

The key aspect to interfaces in typescript that distinguish them from types is that they can be extended with new functionality after they've already been declared.

So by using the type guard, typescript now knows whether the is a or , so the corresponding APIs can be called without any design time linting errors. If it is "Super Critical" for that API to be …

Apr 3, 2018 · What does the <T> mean? That is TypeScript's Generics declaration. Excerpt: A major part of software engineering is building components that not only have well-defined and …

Jun 22, 2018 · 84 That is a "definite assignment assertion": varname !: sometype informs typescript not to worry about checking if varname might be unassigned (it tells typescript that …

the operation a! produces a value of the type of a with null and undefined excluded Optional chaining finally made it to typescript (3.7) 🎉 The optional chaining operator ?. permits reading …

Jul 20, 2018 · 878 TypeScript 3.0 introduces unknown type, according to their wiki: unknown is now a reserved type name, as it is now a built-in type. Depending on your intended use of …

Mar 24, 2018 · TypeScript has three confusing types: {}, Object, and object. You can't assign undefined nor null to any of those types except if the strictNullChecks compiler option is disabled.

Apr 24, 2018 · Note: Since TypeScript 2.9, you can use the --resolveJsonModule compiler flag to have TypeScript analyze imported .json files and provide correct information regarding their …