¿Qué tal algo como esto?

 const data = [ { "keywords": "set,on,increase,decrease,low,medium,high,forward,backward", "commands": "SET" }, { "keywords": "get,access,retrieve", "commands": "GET" }, { "keywords": "run", "commands": "RUN" }, { "keywords": "stop", "commands": "STOP" } ] const keywordExists = keyword => data.flatMap(({keywords}) => keywords.split(',')).includes(keyword) console.log(keywordExists('increase')) console.log(keywordExists('decrease')) console.log(keywordExists('not valid keyword'))

Creo que esto debe ser trabajo.

 const keys = [ { "keywords": "set,on,increease,decrease,low,medium,high,forward,backward", "commands": "SET" }, { "keywords": "get,access,retrieve", "commands": "GET" }, { "keywords": "run", "commands": "RUN" }, { "keywords": "stop", "commands": "STOP" } ] function check(value) { // On every value on keys get index for (let i in keys) { // Get key from keys with index value const key = keys[i]; // Check if is matching if (key.keywords.split(',').includes(value)) // If successfuly matching is found return commands value return key.commands; } // If any result doesnt returned, return null. return null; }