NodeJs Lesson: "in" and "of" used with for loops.

forLoopLesson.js

'use strict';

const obj = {

    obj_key_1: 'obj_value_1',
    obj_key_2: 'obj_value_2',
    obj_key_3: 'obj_value_3'
};

const arr = [ 'array_value_1', 'array_value_2', 'array_value_3' ];



for( let key in obj ) {

    console.log( key );
}



for( let key in obj ) {

    let value = obj[ key ];

    console.log( value );
}



for( let index in arr ) {

    console.log( index );
}



for( let value of arr ) {

    console.log( value );
}

/*
    running this file in node logs the following:

    obj_key_1
    obj_key_2
    obj_key_3
    obj_value_1
    obj_value_2
    obj_value_3
    0   // these numbers are the array indicies
    1
    2
    array_value_1
    array_value_2
    array_value_3
*/

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