Please find below general problematic regarding object iteration and queries.
Here is an object list (aimed at managing a connexion form) :
const connexionData = {
mail: {
value: false,
isRequired: true
},
password: {
value: false,
isRequired: true
},
name: {
value: false,
isRequired: false
},
}
Here is an array variable which stores all the object from connexionData
const fieldstocheck = [connexionData.mail, connexionData.password, connexionData.name]
And the purpose of the function check below is to check if:
For each object in fieldstocheck where isRequired is true, if value is false, return true, or else, return false
const check = () => {
if((fieldstocheck.filter(key =>
key.isRequired).every(val =>
!val.value))) {
return true
} else {
return false
}
}
This function does the job in general. With current object values, it returns true, and false if values are changed to true or to ""
But I was wondering if there would be a faster or mor elegant way of reaching the same goal.
and, yes, have a nice day everyone
The result you're after is a boolean, but you're currently using .filter() which creates an intermediate array. You can remove the .filter() and instead call .every() directly on fieldstocheck array to avoid creating a new array in memory. Removing the filter also does fewer iterations as you're only iterating your array once:
const connexionData = { mail: { value: false, isRequired: true }, password: { value: false, isRequired: true }, name: { value: false, isRequired: false }, }
const fieldstocheck = [connexionData.mail, connexionData.password, connexionData.name];
const res = fieldstocheck.every((obj) => !obj.isRequired || !obj.value);
console.log(res);In the above, we first check if isRequired is false with !obj.isRequired. If it is false then the .every() callback method returns true for that object (as we're negating ! isRequired). When the first operand for || is truthy, the || short-ciruits and so we don't worry about checking right-hand side of the ||. Otherwise, if isRequired is true, we check the right-hand side of the condition to check if the obj.value is false: !obj.value.
In propsitonal logic, the above condition:
!obj.isRequired || !obj.value
is logically equivalent to
!(obj.isRequired && obj.value)
(see De Morgan's law for more details), so we could have also used this as our condition also. You could interpret this as: if the object is required and has a value, then return false, otherwise, true (if it isn't required or doesn't have a value).