FAQ: Introduction to JavaScript - Built-in Objects


This community-built FAQ covers the “Built-in Objects” exercise from the lesson "Introduction to JavaScript ".

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This exercise can be found in the following Codecademy content:

Web Development

Introduction To JavaScript

FAQs on the exercise Built-in Objects

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Why is “console.log(Number.isInteger(2017));” used for determining whether 2017 is a whole number, and not "console.log(2017.isInteger()) ?


I think its because your calling the function or whatever, or what you want to do with it, first. Its kinda like how yoda talks. “to the garbage, take this item” or something like that. so instead of is 2017 an integer, its “is an integer, 2017?”…I think


When you’re using a method on an object (in this case the isInteger method on the number object)- Do I always have to refer to the general Object first? (Here: Number.) As in, does it apply to methods on other objects? Also I’m wondering why this doesn’t work (without “Number”): console.log(isInteger(2017)) …?


This section talks about using Math.floor(Math.random()*50); to get a number between 0 and 50.
But Math.random generates a number in the range 0–1 (inclusive of 0, but not 1) and
Math.floor rounds DOWN to the nearest whole number. So… to get a number that is between 0 and 50, wouldn’t we actually need to multiply by 51?