How can I add a key/value pair to a JavaScript object

• Add key/value pair to javascript object using dot notation

  <script>
  const obj = {
      key1: 'value1',
      key2: 'value2'
  };
  obj.key3 = "value3";
  console.log(obj);
  </script>
  

  Output:

  { key1: 'value1', key2: 'value2', key3: 'value3' }

  You have to use dot notation in between object and new key (object.key) and assign value to key using assignment operator (=) in javascript to add a new key and value pair to an existing javascript object. 

• Add key/value pair to javascript object usign square bracket notation

  <script>
  const obj = {
      key1: 'value1',
      key2: 'value2'
  };
  obj["key3"] = "value3";
  console.log(obj); 
  </script>
  

  Output:

  { key1: 'value1', key2: 'value2', key3: 'value3' }

  You can add a new key/value pair to object in javascript using square ([]) notation. It will helps you to add a new values (key/value) to an existing object in javascript.

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