preact-arco-design/es/Form/hooks/useWatch.js

Arco Design React UI Library.

var __read = this && this.__read || function (o, n) {
  var m = typeof Symbol === "function" && o[Symbol.iterator];
  if (!m) return o;
  var i = m.call(o),
      r,
      ar = [],
      e;

  try {
    while ((n === void 0 || n-- > 0) && !(r = i.next()).done) {
      ar.push(r.value);
    }
  } catch (error) {
    e = {
      error: error
    };
  } finally {
    try {
      if (r && !r.done && (m = i["return"])) m.call(i);
    } finally {
      if (e) throw e.error;
    }
  }

  return ar;
};

import { useState, useContext, useEffect, useRef } from "preact/compat";
import get from 'lodash/get';
import { isArray, isString } from "../../_util/is";
import { FormContext } from "../context";
import warn from "../../_util/warning";

var useWatch = function useWatch(field, form) {
  var formCtx = useContext(FormContext);
  var formInstance = form || formCtx.store;

  var _a = __read(useState(function () {
    var fieldValues = formInstance === null || formInstance === void 0 ? void 0 : formInstance.getFieldsValue([].concat(field));

    if (isString(field)) {
      return get(fieldValues, field);
    }

    return fieldValues;
  }), 2),
      value = _a[0],
      setValue = _a[1];

  var valueRef = useRef(JSON.stringify(value));
  useEffect(function () {
    if (!formInstance) {
      warn(true, 'formInstance is not available');
      return;
    }

    var registerWatcher = (formInstance === null || formInstance === void 0 ? void 0 : formInstance.getInnerMethods(true)).registerWatcher;

    var updateValue = function updateValue() {
      var formValues = formInstance.getFieldsValue([].concat(field));
      var newValue = formValues;

      if (!isArray(field)) {
        newValue = get(formValues, field);
      }

      var newValueString = JSON.stringify(newValue);

      if (valueRef.current !== newValueString) {
        setValue(newValue);
        valueRef.current = newValueString;
      }
    };

    updateValue();
    var cancelWatch = registerWatcher && registerWatcher(updateValue);
    return function () {
      cancelWatch && cancelWatch();
    };
  }, []);
  return value;
};

export default useWatch;