key-searcher

Lightweight utility to recursively search for keys in JSON objects and return a filtered object with matching keys.

Installation

npm install key-searcher

What it does ?

• Traverses objects recursively
• Finds matching keys at any depth
• Returns a new object containing only the matched keys
• Preserves the original structure where matches are found
• Does not mutate the original object

Example

import searchIn from "key-searcher";

//Given a JSON object with nested keys like the following:
const obj1 = {
  key1: false,
  key2: {
    key3: "val2",
    key4: {
      key5: "val3",
      key6: {
        key7: "val4",
        key8: {
          key9: "val5",
        },
      },
    },
    key5: "val4",
  },
  key10: { key11: "val6" },
};

//when passing it as the first argument to the function, in addition to the keys you want to search for
const newJSON = searchIn(obj1, "key25", "key1", "key6");

//the result will look like the following:
{
  key25: undefined,
  key1: false,
  key6: { key7: 'val4', key8: { key9: 'val5' } }
}

Behavior & Notes

• What happens if a key is not found? The result will be set to undefined.
• If the value of a key is a nested object, the entire subtree of that object will appear in the result, as shown with key6 in the example.
• The original JSON is not modified during the search.
• Only matching branches are preserved in the output.

Use Cases

• Filtering API responses
• Extracting specific fields from deeply nested data
• Cleaning large JSON structures