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Programming TypeScript
book

Programming TypeScript

by Boris Cherny
May 2019
Intermediate to advanced content levelIntermediate to advanced
322 pages
7h 6m
English
O'Reilly Media, Inc.
Book available
Content preview from Programming TypeScript

Appendix F. TSC Compiler Flags for Safety

Tip

For a complete list of available compiler flags, head over to the TypeScript Handbook website.

Each TypeScript release introduces new checks that you can enable to squeeze even more safety out of your code. Some of these flags—prefixed with strict—are included as part of the strict flag; or, you can opt into strict flags one at a time. Table F-1 lists the compiler flags related to safety that are available at the time of writing.

Table F-1. TSC safety flags
Flag Description

alwaysStrict

Emit 'use strict'.

noEmitOnError

Don’t emit JavaScript when your code has type errors.

noFallthroughCasesInSwitch

Make sure that every switch case either returns a value or breaks.

noImplicitAny

Error when a variable’s type is inferred as any.

noImplicitReturns

Make sure that every code path in every function explicitly returns. See “Totality”.

noImplicitThis

Error when you use this in a function without explicitly annotating the this type. See “Typing this”.

noUnusedLocals

Warn about unused local variables.

noUnusedParameters

Warn about unused function parameters. Prefix your parameter name with _ to ignore this error.

strictBindCallApply

Enforce type safety for bind, call, and apply. See “call, apply, and bind”.

strictFunctionTypes

Enforce that functions are contravariant in their parameter and this types. See “Function variance”.

strictNullChecks

Promote null to a type. See “null, undefined, void, and never”.

strictPropertyInitialization ...

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Publisher Resources

ISBN: 9781492037644Errata PageSupplemental Content