December 2017
Beginner
372 pages
10h 32m
English
Content preview from TypeScript 2.x By Example
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Let and const keywords
The let and const keywords solve these problems by providing block scoping for the variables, and do not support hoisting. Block scoping means that the scope of a variable is restricted to the scope in which it is declared, which is normally defined by curly braces. So, if a variable is defined inside a loop or an if condition, that variable is not available outside this block, as seen in the following example. Line 6 throws an exception of x is not defined, but we do get the correct response of 10 on line 4:
This helps reduce errors in code because we make sure we are using the variables in the correct scope. Also, ...
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.