Today I learned...
The || OR operator
- represented by two vertical lines
- if any of the values are true, it will return true
- if the operand is not boolean, it is converted to a boolean for evaluation
- returns the first true value with the original value of the operand, does not continue to evaluate operands in the expression (also known as "short circuit evaluation")
- return the last false value if all operands evaluated and are false *A value is returned in its original form, not the conversion. In a chain of || OR, the first truthy value is returned or the last one if no truthy value is found.
The && AND operator
- represented by two ampersands &&
- returns true if both operands are true and false otherwise
- returns the first falsy value
- returns the last value if all values are true
- && (AND) has a higher precedence then || (OR)
The ! NOT operator
- represented with an exclamation !
- converts value to boolean then returns the inverse value
- higher precedence then && (AND) and || (OR)
- !! can be used to convert value to a boolean
Switch Statement
An alternative to the if..else statements when checking for matching values of a single expression\value input.
const color = 'blue';
switch (color){ // expression or value
case 'red':
console.log('Color is red');
break;
case 'blue': // choice matches the expression/value 'blue'
console.log('Color is blue');
break; // if the previous choice matches, stop executing the code block or it will continue to the next choice
case 'green':
console.log('Color is green');
break;
default: // will run if none of the choice matches, do not need a break statement because there are not more statements after to execute
console.log('No matches');
}
Resources
The Odin Project
https://developer.mozilla.org/en-US/docs/Learn/JavaScript/Building_blocks/conditionals
https://developer.mozilla.org/en-US/docs/Learn/JavaScript/Building_blocks/conditionals
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