@blueprintjs/core
Version:
Core styles & components
158 lines • 5.96 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.
*/
/** @returns true if React is running in a client environment, and false if it's in a server */
export function hasDOMEnvironment() {
return typeof window !== "undefined" && window.document != null;
}
export function elementIsOrContains(element, testElement) {
return element === testElement || element.contains(testElement);
}
/**
* Checks whether the given element is inside something that looks like a text input.
* This is particularly useful to determine if a keyboard event inside this element should take priority over hotkey
* bindings / keyboard shortcut handlers.
*
* @returns true if the element is inside a text input
*/
export function elementIsTextInput(elem) {
// we check these cases for unit testing, but this should not happen
// during normal operation
if (elem == null || elem.closest == null) {
return false;
}
const editable = elem.closest("input, textarea, [contenteditable=true]");
if (editable == null) {
return false;
}
// don't let checkboxes, switches, and radio buttons prevent hotkey behavior
if (editable.tagName.toLowerCase() === "input") {
const inputType = editable.type;
if (inputType === "checkbox" || inputType === "radio") {
return false;
}
}
// don't let read-only fields prevent hotkey behavior
if (editable.readOnly) {
return false;
}
return true;
}
/**
* Gets the active element in the document or shadow root (if an element is provided, and it's in the shadow DOM).
*/
export function getActiveElement(element, options) {
const rootNode = (element?.getRootNode(options) ?? document);
const activeElement = rootNode.activeElement;
return activeElement instanceof HTMLElement ? activeElement : null;
}
/**
* Throttle an event on an EventTarget by wrapping it in a
* `requestAnimationFrame` call. Returns the event handler that was bound to
* given eventName so you can clean up after yourself.
*
* @see https://developer.mozilla.org/en-US/docs/Web/Events/scroll
*/
/* istanbul ignore next */
export function throttleEvent(target, eventName, newEventName) {
const throttledFunc = throttleImpl((event) => {
target.dispatchEvent(new CustomEvent(newEventName, event));
});
target.addEventListener(eventName, throttledFunc);
return throttledFunc;
}
/**
* Throttle a callback by wrapping it in a `requestAnimationFrame` call. Returns
* the throttled function.
*
* @see https://www.html5rocks.com/en/tutorials/speed/animations/
*/
export function throttleReactEventCallback(callback, options = {}) {
const throttledFunc = throttleImpl(callback, (event2) => {
if (options.preventDefault) {
event2.preventDefault();
}
},
// prevent React from reclaiming the event object before we reference it
(event2) => event2.persist());
return throttledFunc;
}
/**
* Throttle a method by wrapping it in a `requestAnimationFrame` call. Returns
* the throttled function.
*/
/* istanbul ignore next */
// eslint-disable-next-line @typescript-eslint/no-unsafe-function-type
export function throttle(method) {
return throttleImpl(method);
}
// eslint-disable-next-line @typescript-eslint/no-unsafe-function-type
function throttleImpl(onAnimationFrameRequested, onBeforeIsRunningCheck, onAfterIsRunningCheck) {
let isRunning = false;
const func = (...args) => {
onBeforeIsRunningCheck?.(...args);
if (isRunning) {
return;
}
isRunning = true;
onAfterIsRunningCheck?.(...args);
requestAnimationFrame(() => {
onAnimationFrameRequested(...args);
isRunning = false;
});
};
return func;
}
export function clickElementOnKeyPress(keys) {
return (e) => {
if (keys.some(key => e.key === key)) {
// Prevent spacebar from scrolling the page unless we're in a text field
if (!elementIsTextInput(e.target)) {
e.preventDefault();
}
e.target.dispatchEvent(new MouseEvent("click", { ...e, view: undefined }));
}
};
}
/**
* Selector for all possible focusable items.
*
* Derived from this SO question: {@link https://stackoverflow.com/questions/1599660/which-html-elements-can-receive-focus}
*
* Note: Order may not be correct if children elements use tabindex values > 0.
*/
const SELECTOR_FOCUSABLE = [
'a[href]:not([tabindex="-1"])',
'button:not([disabled]):not([tabindex="-1"])',
'details:not([tabindex="-1"])',
'input:not([disabled]):not([tabindex="-1"])',
'select:not([disabled]):not([tabindex="-1"])',
'textarea:not([disabled]):not([tabindex="-1"])',
'[tabindex]:not([tabindex="-1"])',
].join(",");
/**
* Gets all focusable elements within the given element.
*
* Selector derived from this SO question: {@link https://stackoverflow.com/questions/1599660/which-html-elements-can-receive-focus}
*
* Note: Order may not be correct if children elements use tabindex values > 0.
*
* @param {HTMLElement} element - The element to search within.
* @returns {HTMLElement[]} An array of focusable elements.
*/
export function getFocusableElements(element) {
return Array.from(element.querySelectorAll(SELECTOR_FOCUSABLE));
}
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