Today is the 5th day of my #100DaysOfCode journey with JavaScript.
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This Article is a part of the JavaScript Fundamentals series.
Console Log
The console.log
will log values during the program’s execution. If we console.log
a value, that value will show in our test results. You will also often see console.log
used in code examples:
let a = 22;
a = a + 10;
console.log(a); // 32;
Conditionals
Conditional statements control behaviour in JavaScript and determine whether or not pieces of code can run.
if
StatementUse of
if
when needing to branch based on a condition:if(1 === 1) { console.log( "Yes, it's true!" ); }
In the above line,
1 === 1
is the condition. The===
operator referred to as the strict equality operator. It compares two values and evaluates them to betrue
if they are equal.Example: Let’s complete the isEqual function! If a is equal to b return true.
function isEqual(a, b) { return(a===b); }
!==
or Is Not Equal referred to as a strict inequality operator. This operator will evaluate totrue
if the two values are not equal.console.log( 1 !== 2 ); // true console.log( 2 !== 2 ); // false console.log( 3 !== 2 ); // true
Example: Let’s complete the
isNotEqual
function! Ifa
is not equal tob
returntrue
.function isNotEqual(a, b) { if(a !== b){ return true; } }
else
StatementThe
else
statement runs only if theif
condition is not true.if(isRaining === true) { stayIndoors(); } else { // isRaining is not true goOutside(); }
Example: Let’s update our
isNotEqual
function to also handle the case wherea
is equal tob
. If a is not equal tob
return true. Otherwise, returnfalse
.function greater(first, last) { if (first > last){ return first; } if (last > first) { return last; } }
Let’s take a look at two new operators, greater than
>
and less than<
operators! Both>
and<
will evaluate tofalse
if the operands are equal:console.log(1 > 3); // false console.log(3 > 1); // true console.log(3 < 1); // false console.log(1 < 3); // true
The values on either side of the operator are referred to as “operands”. The operands for the equation
1 > 3
are1
and3
.>=
or<=
OperatorBoth
>=
and<=
will evaluate totrue
when the operands are equal, unlike the>
and<
operators.function greaterThanOrEqualTo(a, b) { if(a > b) { return true; } if(a === b) { return true; } } // or // Both will accomplish the same functionality. function isEqual(a,b) { if(a === b) { return true; } return false; }
else If
StatementWe can use
else
andif
together:if(firstCondition) { // firstCondition is true } else if (otherCondition) { // firstCondition is not true and otherCondition is true } else { // neither condition is true }
What happens if the two conditions were
true
?const a = true; const b = true; if(a) { // this will run } else if (b) { // this will not run! } else { // this will definitely not run. }
The important thing to take away from this is that
else
statements will only run if the original condition is nottrue
.
Conclusion
Ending with an extra bit of information about JavaScript…
In order to guarantee that code is readable to a standard, many organisations maintain a rigid style guide. {}
are typically recommended for if/else
statements.
Today I learned about Conditionals, If, Else, Else If in JavaScript.