@blueprintjs/core
Version:
Core styles & components
104 lines • 5.42 kB
JavaScript
/* !
* Copyright 2020 Palantir Technologies, Inc. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import * as React from "react";
import { AbstractPureComponent, DISPLAYNAME_PREFIX } from "../../common";
/**
* A stateful wrapper around the low-level <input> component which works around a
* [React bug](https://github.com/facebook/react/issues/3926). This bug is reproduced when an input
* receives CompositionEvents (for example, through IME composition) and has its value prop updated
* asychronously. This might happen if a component chooses to do async validation of a value
* returned by the input's `onChange` callback.
*
* Note: this component does not apply any Blueprint-specific styling.
*/
export class AsyncControllableInput extends AbstractPureComponent {
static displayName = `${DISPLAYNAME_PREFIX}.AsyncControllableInput`;
/**
* The amount of time (in milliseconds) which the input will wait after a compositionEnd event before
* unlocking its state value for external updates via props. See `handleCompositionEnd` for more details.
*/
static COMPOSITION_END_DELAY = 10;
state = {
hasPendingUpdate: false,
isComposing: false,
nextValue: this.props.value,
value: this.props.value,
};
cancelPendingCompositionEnd = null;
static getDerivedStateFromProps(nextProps, nextState) {
if (nextState.isComposing || nextProps.value === undefined) {
// don't derive anything from props if:
// - in uncontrolled mode, OR
// - currently composing, since we'll do that after composition ends
return null;
}
const userTriggeredUpdate = nextState.nextValue !== nextState.value;
if (userTriggeredUpdate) {
if (nextProps.value === nextState.nextValue) {
// parent has processed and accepted our update
if (nextState.hasPendingUpdate) {
return { value: nextProps.value, hasPendingUpdate: false };
}
else {
return { value: nextState.nextValue };
}
}
else {
if (nextProps.value === nextState.value) {
// we have sent the update to our parent, but it has not been processed yet. just wait.
// DO NOT set nextValue here, since that will temporarily render a potentially stale controlled value,
// causing the cursor to jump once the new value is accepted
return { hasPendingUpdate: true };
}
// accept controlled update overriding user action
return { value: nextProps.value, nextValue: nextProps.value, hasPendingUpdate: false };
}
}
else {
// accept controlled update, could be confirming or denying user action
return { value: nextProps.value, nextValue: nextProps.value, hasPendingUpdate: false };
}
}
render() {
const { isComposing, hasPendingUpdate, value, nextValue } = this.state;
const { inputRef, ...restProps } = this.props;
return (React.createElement("input", { ...restProps, ref: inputRef,
// render the pending value even if it is not confirmed by a parent's async controlled update
// so that the cursor does not jump to the end of input as reported in
// https://github.com/palantir/blueprint/issues/4298
value: isComposing || hasPendingUpdate ? nextValue : value, onCompositionStart: this.handleCompositionStart, onCompositionEnd: this.handleCompositionEnd, onChange: this.handleChange }));
}
handleCompositionStart = (e) => {
this.cancelPendingCompositionEnd?.();
this.setState({ isComposing: true });
this.props.onCompositionStart?.(e);
};
handleCompositionEnd = (e) => {
// In some non-latin languages, a keystroke can end a composition event and immediately afterwards start another.
// This can lead to unexpected characters showing up in the text input. In order to circumvent this problem, we
// use a timeout which creates a delay which merges the two composition events, creating a more natural and predictable UX.
// `this.state.nextValue` will become "locked" (it cannot be overwritten by the `value` prop) until a delay (10ms) has
// passed without a new composition event starting.
this.cancelPendingCompositionEnd = this.setTimeout(() => this.setState({ isComposing: false }), AsyncControllableInput.COMPOSITION_END_DELAY);
this.props.onCompositionEnd?.(e);
};
handleChange = (e) => {
const { value } = e.target;
this.setState({ nextValue: value });
this.props.onChange?.(e);
};
}
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