"Inner Experience is only one source of human Knowledge."
- Dr. Allama Muhammad Iqbal
Good Day!!
In this article, we would be discussing the Set object in JavaScript
- Set
-
Instance properties
size
-
Instance methods
add(value)delete(value)clear()has(value)
-
Iteration methods
keys()values()entries()forEach()
- Remove duplicate items from array using Set
Let's Start.....
1. Set
The Set object lets you store unique values of any type, whether primitive values or object references.
Description
Set objects are collections of values. You can iterate through the elements of a set in insertion order. A value in the Set may only occur once; it is unique in the Set's collection.
Example
const setObj= new Set();
setObj.add("anyString");
setObj.add(11);
setObj.add(true);
setObj.add({key:"value"});
console.log("Data in Set is ",setObj)
// Data in Set is Set(4) {"anyString", 11, true, {key:"value"}}
2. Instance properties
-
size: Returns the number of values in
Setobject
const setObj= new Set();
setObj.add("anyString");
setObj.add(11);
setObj.add(true);
setObj.add({key:"value"});
console.log("Size of Set is ",setObj.size)
// Size of Set is 4
3. Instance methods
-
add(value):Appendsvalueto theSetobject. Return theSetobject with added value
const setObj= new Set();
setObj.add("addedString");
console.log("First value added String ", setObj);
// First Value added String Set(1) {"addedString"}
setObj.add(11);
console.log("second value added number", setObj);
// second value added number Set(2) {"addedString", 11}
-
delete(value):Removes the element associated to the value and returns abooleanasserting whether an element was successfully removed or not.
const setObj= new Set();
setObj.add("addedString");
console.log("Delete addedString from setObj ", setObj.delete("addedString"));
// Delete addedString from setObj true
-
clear():Removes all elements from theSetobject.
const setObj= new Set();
setObj.add("anyString");
setObj.add(11);
setObj.add(true);
setObj.add({key:"value"});
console.log("Data in Set is ",setObj)
// Data in Set is Set(4) {"anyString", 11, true, {key:"value"}}
//Now clear setObj
setObj.clear();
console.log("Data in Set after clear ",setObj)
// Data in Set after clear Set(0) {}
-
has(value):Returns abooleanasserting whether an element is present with the given value in theSetobject or not.
const setObj= new Set();
setObj.add("anyString");
setObj.add(11);
setObj.add(true);
setObj.add({key:"value"});
console.log("Data in Set is ",setObj)
// Data in Set is Set(4) {"anyString", 11, true, {key:"value"}}
//Now check value exist or not in setObj
console.log("11 exists in setObj ",setObj.has(11));
// 11 exists in setObj true
4. Iteration methods
-
keys() && values():Returns a new iterator object that yields the values for each element in theSetobject in insertion order. (For Sets,keys()&&values()methods are same.)
const setObj= new Set();
setObj.add("anyString");
setObj.add(11);
setObj.add(true);
setObj.add({key:"value"});
for (let item of setObj.keys()) console.log('Item: ',item)
// Item: anyString
// Item: 11
// Item: true
// Item: {key:"value"}
for (let item of setObj.values()) console.log('Item: ',item)
// Item: anyString
// Item: 11
// Item: true
// Item: {key:"value"}
-
forEach(callbackFn[, thisArg]):CallscallbackFnonce for each value present in theSetobject, in insertion order. If athisArgparameter is provided, it will be used as thethisvalue for each invocation ofcallbackFn.
const setObj= new Set();
setObj.add("anyString");
setObj.add(11);
setObj.add(true);
setObj.add({key:"value"});
setObj.forEach((value)=>{
console.log('Value: ',value)
})
// Value: anyString
// Value: 11
// Value: true
// Value: {key:"value"}
5. Remove duplicate items from array using Set
const duplicateNumbers = [11,45,33,11,22,44,44,44,56,76,45];
console.log('duplicate removed ',[...new Set(duplicateNumbers)]);
// duplicate removed (7) [11,45,33,22,44,56,76]
const dupNames=["John","Daina","John","Jason","Joe","Daina"];
console.log('duplicate removed ',[...new Set(dupNames)]);
// duplicate removed (4) ["John", "Daina", "Jason", "Joe"]
Here it's official documentation
Set in JavaScript Official
Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.
Thank you
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