[].slice.call(
[] // Array object
.slice // Accessing the function 'slice' present in the prototype of Array
.call // Accessing the function 'call' present in the prototype of function object(slice)
(document.querySelectorAll('a'),0)
// 'call' can have arguments like, (thisArg, arg1,arg2...n).
// So here we are passing the 'thisArg' as an array like object,
// that is a 'nodeList'. It will be served as 'this' object inside of slice function.
// And finally setting 'start' argument of slice as '0' and leaving the 'end'
// argument as 'undefined'