Conditional filter using Knex.js and SQL with multiple search criteria

You can conditionally build your query with the knex query builder:

const getFilteredItems = (searchCriteria) => knex('items')
  .where((qb) => {
    if (searchCriteria.searchTerm) {
      qb.where('items.itemName', 'like', `%${searchCriteria.searchTerm}%`);
    }

    if (searchCriteria.itemType) {
      qb.orWhere('items.itemType', '=', searchCriteria.itemType);
    }

    if (searchCriteria.category) {
      qb.orWhere('items.category', '=', searchCriteria.category);
    }
  });

You can also use this instead of accepting a querybuilder argument as in the example @abdulbarik gave, but I think it is less explicit.

You can try the following :

const getFilteredItems = (searchCriteria) => knex('items')
  .where('items.itemName', 'like', `%${searchCriteria.searchTerm || ''}%`)
  .where('items.itemType', 'like', `%${searchCriteria.itemType || ''}%`)
  .where('items.category', 'like', `%${searchCriteria.category || ''}%`)

If any parameter is missing or undefined, it will match the field to be like '%%' which effectively means, don't care about this parameter.