To find and remove objects in an array based on a key value in JavaScript, we can use the filter method.
For instance, we write
myArray = myArray.filter((obj) => {
return obj.id !== id;
});
to call myArray.filter with a callback that returns an array with the objects with id property that doesn’t equal id.
And then we assign the returned array back to myArray to update it.
To use optional chaining with arrays and functions with JavaScript, we use the ?. operator.
For instance, we write
const item = myArray.filter((x) => x.testKey === myTestKey)?.[0];
to call filter to return an array with items in myArray where the testKey property equals myTestKey.
And we get the first item with the optional chaining operator with ?.[0].
To use JavaScript foreach loop on an associative array object, we use the Object.entries method.
For instance, we write
const h = {
a: 1,
b: 2,
};
Object.entries(h).forEach(([key, value]) => console.log(value));
to call Object.entries with h to return a key-value pair array.
Then we call forEach with a callback that destructures the key and value from the array.
And we log the property value of each entry.
To find the largest number contained in a JavaScript array, we use the Math.max method and the spread operator.
For instance, we write
const arr = [1, 2, 3];
const max = Math.max(...arr);
to call Math.max with the entries in the arr array as arguments.
We use the spread operator to spread the entries as arguments.
To search and remove string within a JavaScript array, we use the filter method.
For instance, we write
const arr = ["A", "B", "C"];
const filteredArr = arr.filter((e) => e !== "B");
to call arr.filter to return an array without 'B' in it.