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Learning TypeScript 2.x - Second Edition
book

Learning TypeScript 2.x - Second Edition

by Remo H. Jansen
April 2018
Beginner content levelBeginner
536 pages
13h 21m
English
Packt Publishing
Content preview from Learning TypeScript 2.x - Second Edition

Non-nullable types

TypeScript 2.0 introduced what are known as non-nullable types. TypeScript used to consider null and undefined to be valid values of every type.

The following diagram represents the values that can be assigned to the type number when non-nullable types are disabled:

As we can see in the preceding diagram, undefined and null are allowed as values of the type number, together with the NaN value and all the possible numbers.

NaN, standing for not a number, is a numeric data type value representing an undefined or non-representable value, especially in floating-point calculations. Systematic use of NaNs was introduced by the ...
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Publisher Resources

ISBN: 9781788391474Supplemental Content