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Enumerable vs iterable
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| //enumerable vs iterable | |
| //enumerable is a keyword in every object...and it's by default true | |
| //this means that if you loop through the object using a for...in, it all properties | |
| //will be looped through except where a property' enumerable is defined as false. | |
| //see below | |
| let log = console.log; | |
| let names =["Maxon","Moureen", "Kaihura-nkuba"]; | |
| names.elf = "Lindolf"; | |
| Object.defineProperty(names, "ent",{ name: "Treebard", enumerable: true}); | |
| //by setting enumerable to false above, we cant find this if we loop through | |
| //setting enumerable to true, we can see it | |
| log(names) | |
| for (prop in names){ | |
| log(prop); //"0" ,"1" ,"2" ,"elf" | |
| } | |
| //Example 2 | |
| let middleEarth = { | |
| 'towns': ["Antact", "Tica"], | |
| 'races': ["Muk", "Ama", "Pendo"] | |
| } | |
| middleEarth.creator = "A.R.R Beader"; | |
| Object.defineProperty(middleEarth, "age",{ value: "3rd", enumerable: true}); | |
| for (prop in middleEarth){ | |
| log(prop); //"0" ,"1" ,"2" ,"elf" | |
| } | |
| //objeccts by default are not iterable | |
| //This means that if we try to loop through 'middleEarth',fails because | |
| //it is an object | |
| //looping through names however returns only those that were not created by the prototype... making these below | |
| //iterable | |
| //Enumerable values are not iterable | |
| for (let p of names){ | |
| log(p);//maxon, moreen, Kaihura-nkuba | |
| } |
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