Short JavaScript Solution.
Time Complexity : O(n)\njavascript []\nvar checkIfPangram = function(sentence) {\n    return new Set(sentence.split("")).size == 26;\n};\n\n
**Time Complexity : O(n)**\n```javascript []\nvar checkIfPangram = function(sentence) {\n    return new Set(sentence.split("")).size == 26;\n};\n```\n
['JavaScript']