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Basics

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Q - What is the !! (not not) operator in JavaScript?

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Reference - https://love2dev.com/blog/javascript-not-operator/

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This is really a shorthand way to convert any value to a boolean.

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Some say the way to remember this trick is, “bang bang, you’re boolean”.

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Q - What are the things that evaluate to falsey in JavaScript?

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Reference - https://love2dev.com/blog/javascript-not-operator/

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Q - What is AMD, CommonJS, and UMD?

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Reference - https://www.davidbcalhoun.com/2014/what-is-amd-commonjs-and-umd/

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Q - Define primitive types.

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A primitive (primitive value, primitive data type) is data that is not an object and has no methods.

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All primitives are immutable, i.e., they cannot be altered.

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Q - What are the primitive types in JavaScript?

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  1. String : typeof instance === "string"
    2. \n
  2. Number : typeof instance === "number"
    3. \n
  3. Boolean : typeof instance === "boolean"
    4. \n
  4. BigInt : typeof instance === "bigint"
    5. \n
  5. undefined : typeof instance === "undefined"
    6. \n
  6. Symbol : typeof instance === "symbol"
    7. \n
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Reference - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures

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Q - What are the non-primitive types (Object references) in JavaScript?

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  1. null : typeof instance === "object"
    2. \n
  2. \n

    Object : typeof instance === "object"\nSpecial non data but Structural type for any constructed instance

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    new Object, new Array, new Map, new Set, new WeakMap, new WeakSet, new Date and almost everything made with new keyword;

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    3. \n
  3. Function: typeof instance === "function"
    4. \n
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Q - What is a Closure?

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A closure is the combination of a function bundled together (enclosed) with references to its surrounding state (the lexical environment).

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In other words, a closure gives you access to an outer function’s scope from an inner function.

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In other words, a closure is nothing but functions with preserved data.

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Reference - https://medium.com/javascript-scene/master-the-javascript-interview-what-is-a-closure-b2f0d2152b36

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Reference - https://www.youtube.com/watch?v=71AtaJpJHw0&ab_channel=techsith

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Q - Give an example of a closure.

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var addTo = function(passed) {\n  var add = function(inner) {\n    return passed + inner;\n  };\n  return add;\n}\nvar addThree = addTo(3); \nvar addFour = addTo(4);\n\nconsole.log(addThree(1)); // 4\nconsole.log(addFour(1));  // 5
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Reference - https://www.youtube.com/watch?v=71AtaJpJHw0&ab_channel=techsith

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Advanced

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Tree Shaking

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Q - What is tree shaking?

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References

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Q - What is the benefit of tree shaking?

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References

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