How can I check whether a JavaScript object contains a value in it or not?

Question

0:{date: "2021-1-9", views: 32109, clicks: 279, likes: 4391}
1: {date: "2021-1-10", views: 127568, clicks: 691, likes: 8471}
2: {date: "2021-1-11", views: 17304, clicks: 94, likes: 764}
3: {date: "2021-1-12", views: 11008, clicks: 49, likes: 421}

0: {date: "2021-1-9", views: 32109, clicks: 279}
1: {date: "2021-1-10", views: 127568, clicks: 69}
2: {date: "2021-1-11", views: 17304, clicks: 94}
3: {date: "2021-1-12", views: 11008, clicks: 49}

0: {date: "2021-1-9", views: 32109, likes: 4391}
1: {date: "2021-1-10", views: 127568,likes: 8471}
2: {date: "2021-1-11", views: 17304, likes: 764}
3: {date: "2021-1-12", views: 11008, likes: 421}

I have the above data, as you can see some don't have likes, some don't have clicks element, so I want to check whether they exist in the arrays or not and print as false for the particular element which does not exist in the array.

Answer 1

Object.prototype.hasOwnProperty()

You can check with the method hasOwnProperty() if the object has the key or not.

 const obj = [{ date: "2021-1-9", views: 32109, clicks: 279, likes: 4391 }, { date: "2021-1-10", views: 127568, clicks: 691, likes: 8471 }, { date: "2021-1-11", views: 17304, clicks: 94, likes: 764 }, { date: "2021-1-12", views: 11008, clicks: 49, likes: 421 }, { date: "2021-1-9", views: 32109, clicks: 279 }, { date: "2021-1-10", views: 127568, clicks: 69 }, { date: "2021-1-11", views: 17304, clicks: 94 }, { date: "2021-1-12", views: 11008, clicks: 49 }, { date: "2021-1-9", views: 32109, likes: 4391 }, { date: "2021-1-10", views: 127568, likes: 8471 }, { date: "2021-1-11", views: 17304, likes: 764 }, { date: "2021-1-12", views: 11008, likes: 421 } ] let propToLookFor = "likes"; obj.forEach((x) => { if (x.hasOwnProperty(propToLookFor)) { console.log("True"); }else{ console.log("False"); } })