Theo's Typesafe Cult•2y ago

react-hook-form with formatted numeric values

I have an "amount" field which is numeric in my react-hook-form. Since the amounts can grow up to the millions in my case, I want to format the displayed value having a thousand separator for better UX. I looked for libs for formatting these values, and the best (maintained, easy to use, high popularity) I could find was react-number-format, so I gave it a shot. I found some attempts, all telling I might need to make my input "uncontrolled". These are the 2 ways I tried: https://stackoverflow.com/a/69258165/3045531 https://stackoverflow.com/a/63091512/3045531 My problem is that the actual form value linked to the field in the form's context is not numeric but a string, since it's handling the formatted value there, not the numeric one. How can I make the form handle the numeric value instead of the formatted one, so my Zod validation won't fail there? I would prefer not to use coerce in the schema to keep it cleaner.

Stack Overflow

How do I integrate React hook form with NumberFormat (react-number-...

I am trying to use React hook form with NumberFormat without Controller and without ReactDOM.findDOMNode (which is deprecated and discouraged). The following code works import React from 'react'; i...

Stack Overflow

Thousand separator input with React Hooks

I would like to add on a input a thousand separator using React Hooks but I'm not sure how. I have tried the below code so far and is not working. Can you please point out what could be the issue a...

18 Replies

Brendonovich•2y ago

If you do use react-number-format, you can use the onValueChange callback to get the floatValue and pass that to the onChange from Controller/useController

FroxxOP•2y ago

Tried that. Still results in string values:

const NumberInput = (props) => {
  const { name } = props;

  const form = useFormContext();

  // always logs string values
  console.log(form.getValues(name));

  return (
    <Controller
      {...{
        control: form.control,
        name,
        render: ({ field: { value, onChange } }) => (
          <NumericFormat
            {...{ value, onChange }}
            onValueChange={({ floatValue }) => {
              form.setValue(name, floatValue);
            }}
            thousandSeparator=","
          />
        ),
      }}
    />
  );
};

const NumberInput = (props) => {
  const { name } = props;

  const form = useFormContext();

  // always logs string values
  console.log(form.getValues(name));

  return (
    <Controller
      {...{
        control: form.control,
        name,
        render: ({ field: { value, onChange } }) => (
          <NumericFormat
            {...{ value, onChange }}
            onValueChange={({ floatValue }) => {
              form.setValue(name, floatValue);
            }}
            thousandSeparator=","
          />
        ),
      }}
    />
  );
};

Brendonovich•2y ago

Possibly because you're passing both onChange and onValueChange, try calling onChange within onValueChange instead of using setValue

FroxxOP•2y ago

Oh. I tried that before, but also passed onChange to <NumericFormat /> as well just as I did with value. So it probably worked for a moment, but got overwritten instantly. After only passing value and calling onChange within onValueChange that works! Anyway there are still some more problems due to the input being controlled here: - It doesn't respond to a <button type="reset" /> - RHF doesn't auto focus the field after a failed validation - I'd like to hand in my standard input component as customInput to NumericFormat, but since that one is uncontrolled as well, it throws some issues Is there no way to do the formatting in an uncontrolled state?

Brendonovich•2y ago

for point 3 i can say that customInput likely isn't designed for uncontrolled inputs, you'll have to make a custom one out of divs or something For 2 you need to pass field.ref to the component so that it can focus Point 3 i'm not quite sure since the value should get reset internally and propagated on rerender

Finn•2y ago

Brendon when he sees a post about forms todd

Brendonovich•2y ago

yeah i'm kinda the form guy now

FroxxOP•2y ago

Helped me a lot in my last question, so I appreciate it 😄

Brendonovich•2y ago

👀

Finn•2y ago

😩😩😩

Brendonovich•2y ago

make a stackblitz with a basic example and i'll take a look at point 3

FroxxOP•2y ago

I tried that but can't figure out how to actually pass the ref there since it's a functional component, and React doesn't like that

Brendonovich•2y ago

forwardRef assuming that's what u mean

FroxxOP•2y ago

Yeah, I read that in the error message as well, but I don't know how React wants to get that there. I tried this, but it doesn't like it:

    <Controller
      {...{
        control: form.control,
        name,
        render: ({ field: { value, onChange, ref } }) =>
          // eslint-disable-next-line react/display-name
          React.forwardRef(() => (
            <NumericFormat
              {...{ value, ref }}
              onValueChange={({ floatValue }) => {
                onChange(floatValue);
              }}
              thousandSeparator=","

    <Controller
      {...{
        control: form.control,
        name,
        render: ({ field: { value, onChange, ref } }) =>
          // eslint-disable-next-line react/display-name
          React.forwardRef(() => (
            <NumericFormat
              {...{ value, ref }}
              onValueChange={({ floatValue }) => {
                onChange(floatValue);
              }}
              thousandSeparator=","

I don't really know a lot about refs until this point poohheh

taking the 2nd parameter from forwardsRef instead of the one from Controller.render doesn't solve it

Brendonovich•2y ago

try passing ref to getInputRef no need for forwardRef

FroxxOP•2y ago

Ah. That makes sense Well I guess I could go for the controlled number inputs for now. I'm not too happy since the simple "add register(name) to it, and everything works fine in the context"-way of RHF is really handy. Anyway, I get my formatted value this way, my validation works, and those are the main points. Taking care of a working reset functionality etc can be seen as "sugar" for the future. So thanks again to you, @Brendonovich , lord of the forms ✨

Brendonovich•2y ago

yeah for a use case like this you pretty much cannot use uncontrolled inputs, since with uncontrolled inputs the value is derived from the text. glad i could help! also i'd recommend using useController over Controller

FroxxOP•2y ago

True. Hooks are nice. Thanks

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react-hook-form with formatted numeric values