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JavaScript JavaScript Basics (Retired) Making Decisions with Conditional Statements Boolean Values

Derek Sellar
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Derek Sellar
Full Stack JavaScript Techdegree Student 1,339 Points
Posted by Derek Sellar
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Derek Sellar
Full Stack JavaScript Techdegree Student 1,339 Points

correctGuess

Can someone explain why in the second conditional statement we could just write If ( correctGuess) instead of defining it as true/false?

I'm not sure I'm understanding how the code would automatically assume that correctGuess would be true rather than false.

2 Answers

Mark Powell
Mark Powell
8,489 Points

When doing “if checks”, assignment operators can sometimes be omitted.

Longhand:

if (likeJavaScript === true)

Shorthand:

if (likeJavaScript)

Note: these two examples are not exactly equal, as the shorthand check will pass as long as likeJavaScript is a truthy value.

Here is another example. If “a” is NOT equal to true, then do something.

Longhand:

let a; if ( a !== true ) { // do something... }

Shorthand:

let a; if ( !a ) { // do something... }

https://www.sitepoint.com/shorthand-javascript-techniques/

Henrik Christensen
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Henrik Christensen
Python Web Development Techdegree Student 38,322 Points
Henrik Christensen
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Henrik Christensen
Python Web Development Techdegree Student 38,322 Points

if correctGuess contains ANY value (except for 0 or false) it is considered true

const correctGuess = 'Bob';

if (correctGuess) {} // evaluated to true

const correctGuess = '';

if (correctGuess) {} // evaluated to false because '' counts as "no value"

const correctGuess = true;

if (correctGuess) {} // evaluated to true