the murmurous sea

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Strict_mode Strict mode JavaScript's strict mode, introduced in ECMAScript 5, is a way to opt in to a restricted variant of JavaScript, thereby implicitly opting-out of "sloppy mode". Strict mode isn't just a subset: it intentionally has different semantics from normal code. Brow developer.mozilla.org https://m.blog.naver.com/on21..

1. method 2. creates a new array filled with all array elements that pass a test (provided as a function). 3. does not execute the function for array elements without values. 4. does not change the original array. [Syntax] let newArray = arr.filter(callback(element[, index, [array]])[, thisArg]) ▽ callback Required A function to be run for each element in the array. is a predicate, to test each ..

forEach() 1. method 2. executes a provided function once for each array element, in order. 3. for array elements without values? [Syntax] arr.forEach(callback(currentValue [, index [, array]])[, thisArg]) ▽ callback Required Function to execute on each element in the array. function(currentValue, index, arr) currentValue Required. The current element being processed in the array. index Optional...