React JS printing data inside a nested map function in JSX

Question

I am trying to print data inside a nested map function. For some reason it does not print anything. here is what I have:

  {dataFormat.protein_questions.map((item, index) => (
        <div key={_.uniqueId()} className="item">
         <div className="inline fields">
           <Field
              onChange={handleChange}
              name={`protein_question[${index}].units_of_measurement`}
              component="select"
              className="ui dropdown2"
              required>

                 {item.typing_methods.map((method, methodIndex) => {
                    method.unitsOfMeasurement.map((unit, unitIndex) => (
                       <option value={unit.title}>{unit.title}</option>
                    ));
                 })}

          </Field>
         </div>
       </div>
  ))}

The options are not printing any data inside the select for some reason. When I console log the data inside the nested loop it shows fine. Anyone know why this is happening?

By the way this is inside my render function in a JSX view file.

but you are not returing anything from the item.typeing_methods.map, so I am not sure what you are expecting — Icepickle
– Icepickle, Commented Oct 12, 2017 at 9:16
@DhavalRajani no, he is doing it correctly in the other map statements, not that they start with ( and not {, the first will implicitely return the statement, the second expects a return — Icepickle
– Icepickle, Commented Oct 12, 2017 at 9:22
Just out of curiosity, was it one of you two who voted to close this question? — user3574492
– user3574492, Commented Oct 12, 2017 at 9:26
@user3574492 yeah, I did, as for me this is a offtopic as a it is a small I oversight on your part — Icepickle
– Icepickle, Commented Oct 12, 2017 at 17:18

Mikhail Shabrikov · Accepted Answer · 2017-10-12 09:16:23Z

9

It looks like you forgot return before method.unitsOfMeasurement...:

{item.typing_methods.map((method, methodIndex) => {
  return method.unitsOfMeasurement.map((unit, unitIndex) => (
    <option value={unit.title}>{unit.title}</option>
  ));
})}

answered Oct 12, 2017 at 9:16

Mikhail Shabrikov

8,5091 gold badge30 silver badges36 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

user3574492 Over a year ago

Genius! I forgot you had to always return something in the main loop. I'll accept when it lets me.

Collectives™ on Stack Overflow

React JS printing data inside a nested map function in JSX

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related