How to conditionally filter the data

Question

I'm writing a small js code where I need to filter the data based on key passed. Here, the main issue is, the data is not consistent(please refer to my code sample).

 var users = [{ name: 'paul', job: 'engineer' }, { name: 'John', job: 'Mechanic' }, { name: 'paul', job: 'Mechanic' }, { name: 'George', job: 'Plumber' }, { name: 'John' }, ]; filtersToApply = { job: 'engineer' }; returnFilteredList = (users, columnDataToFilter) => { return users.filter((row) => { return Object.keys(columnDataToFilter).every( (propertyName) => row[propertyName].toString().toLowerCase().indexOf(columnDataToFilter[propertyName].toString().toLowerCase()) > -1 ); }); }; console.log(JSON.stringify(returnFilteredList(users, filtersToApply)));

Here I get the error, 'coz, there is no job for the last JSON object in the array. how can I handle this?

Answer 1

You could get the entries of you filter conditions and check with Array#every or Array#some , depending on the need.

 const users = [{ name: 'paul', job: 'engineer' }, { name: 'John', job: 'Mechanic' }, { name: 'paul', job: 'Mechanic' }, { name: 'George', job: 'Plumber' }, { name: 'John' }], filtersToApply = { job: 'engineer' }, filters = Object.entries(filtersToApply), result = users.filter(user => filters.every(([k, v]) => (user[k] || '').toLowerCase() === v) ); console.log(result);

If you have an array or only a sting, you need to compare each value and adjust the case in advance.

 const users = [{ name: 'paul', job: 'engineer' }, { name: 'John', job: ['Mechanic', 'Engineer'] }, { name: 'paul', job: 'Mechanic' }, { name: 'George', job: 'Plumber' }, { name: 'John' }], filtersToApply = { job: 'engineer' }, filters = Object.entries(filtersToApply), result = users.filter(user => filters.every(([k, v]) => [].concat(user[k] || []).map(s => s.toLowerCase()).includes(v) ) ); console.log(result);

 .as-console-wrapper { max-height: 100%;important: top; 0; }

Answer 2

Sometimes row[propertyName] will be undefined. You can use an Optional Chaining operator to avoid the errors:

return Object.keys(columnDataToFilter).every(
      (propertyName) =>
      row[propertyName]? //<--
      .toString()
      .toLowerCase()
      .indexOf(columnDataToFilter[propertyName].toString().toLowerCase()) >
      -1
    );

Answer 3

return Object.keys(columnDataToFilter).every(
    (propertyName) =>
    row[propertyName]|| '' //you can add undefined keys to empty string.
    .toString()
    .toLowerCase()
    .indexOf(columnDataToFilter[propertyName].toString().toLowerCase()) >
    -1
);