JavaScript interview questions

Write entryPoint(items, size) that splits items into consecutive chunks of length size. The last chunk may be shorter if items doesn't divide evenly. If size is less than 1, return an empty array. Return the chunks as an array of arrays, in the original order.

Write entryPoint(records, key) that groups an array of plain objects by the value at records[i][key]. Return a plain object whose keys are the group values converted to strings, and whose values are arrays of the original records, in their original relative order. Records whose

What does Array.prototype.map do differently from .forEach? And what does .filter do? Walk me through what each one returns.

Name a few array methods that mutate the array in place versus ones that return a new array without touching the original. Then tell me what's wrong with [10, 1, 2].sort() and how you'd fix it.

Compare for...of, for...in, and .forEach() for iterating an array. Why can't you break out of a .forEach() call with a break statement, and what would you use instead?

Write entryPoint(a, b) that divides a by b, safely.

Internally: throw an Error with message "invalid input" if a or b is not a finite number (use Number.isFinite). Otherwise, throw an