Add elements conditionally
Create array with conditional elements
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This blog post shows how you can conditionally add elements inside Array literals and properties inside object literals. Conditionally adding elements inside Array literalsThe following code shows how a boolean
This trick works, because the spread operator (
Conditionally adding properties inside object literalsYou can use the proposed spread operator for properties in the same manner. Again, a boolean
The spread operator for object literals does nothing if its operand is an object without enumerable own properties:
Is it worth it?Using the spread operator in this manner leads to slightly cryptic code. Here it is again, for ease of reference:
The crypticity can be worth it if you want to create the Array with a single expression. Different approachesLess cryptic
would be to create the Array with the unconditional elements first and to then conditionally insert elements, via An elegant and self-descriptive solution is to use
Variations of the original approachA variation of the original approach is to use spread and a helper function:
In line A, the triple dots are the rest operator which collects the remaining arguments in an Array and assigns it to Another alternative is to conditionally insert either elements or
Further reading
How do you add a condition to an array?Its pretty simple. Create array with essential elements. Then add conditional elements to the array. Now add other elements if required.
Can we use array in if condition?In other words, it fully supports Intelligent Arrays. For example, if condition «a» is an array of Booleans (true or false values), it returns an array with the same index, containing «b» or «c» as appropriate: Variable X := -2 ..
How do you do an if statement with arrays?If that array is at that first state of [1], and "one". equals(match) then it sets the array to arrayCount[2] and then from there on. Basically, if "one" = match, it should set arrayCount to 2, if "two" = match AND the first if statement has already been executed, it will play the test sound.
How do you find if an element exists in an array in JavaScript?You can use the includes() method in JavaScript to check if an item exists in an array. You can also use it to check if a substring exists within a string. It returns true if the item is found in the array/string and false if the item doesn't exist.
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