gristlabs_grist-core/app/client/components/Clipboard.js

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/**
* Clipboard component manages the copy/cut/paste events by capturing these events from the browser,
* managing their state, and exposing an API to other components to get/set the data.
*
* Because of a lack of standardization of ClipboardEvents between browsers, the way Clipboard
* captures the events is by creating a hidden textarea element that's always focused with some text
* selected. Here is a good write-up of this:
* https://www.lucidchart.com/techblog/2014/12/02/definitive-guide-copying-pasting-javascript/
*
* When ClipboardEvent is detected, Clipboard captures the event and calls the corresponding
* copy/cut/paste/input command actions, which will get called on the appropriate component.
*
* Usage:
* Components need to register copy/cut/paste actions with command.js:
* .copy() should return @pasteObj (defined below).
* .paste(plainText, [cutSelection]) should take a plainText value and an optional cutSelection
* parameter which will specify the selection that should be cleared as part of paste.
* .input(char) should take a single input character and will be called when the user types a
* visible character (useful if component wants to interpret typing into a cell, for example).
*/
/**
* Paste object that should be returned by implementation of `copy`.
*
* @typedef pasteObj {{
* docName: string,
* tableId: string,
* data: object,
* selection: object
* }}
*/
/* global window, document */
var {tsvDecode} = require('app/common/tsvFormat');
var {FocusLayer} = require('app/client/lib/FocusLayer');
var commands = require('./commands');
var dom = require('../lib/dom');
var Base = require('./Base');
var tableUtil = require('../lib/tableUtil');
function Clipboard(app) {
Base.call(this, null);
this._app = app;
this.copypasteField = this.autoDispose(dom('textarea.copypaste.mousetrap', ''));
this.timeoutId = null;
this.onEvent(this.copypasteField, 'input', function(elem, event) {
var value = elem.value;
elem.value = '';
commands.allCommands.input.run(value);
return false;
});
this.onEvent(this.copypasteField, 'copy', this._onCopy);
this.onEvent(this.copypasteField, 'cut', this._onCut);
this.onEvent(this.copypasteField, 'paste', this._onPaste);
document.body.appendChild(this.copypasteField);
FocusLayer.create(this, {
defaultFocusElem: this.copypasteField,
allowFocus: allowFocus,
onDefaultFocus: () => {
this.copypasteField.value = ' ';
this.copypasteField.select();
this._app.trigger('clipboard_focus');
},
onDefaultBlur: () => {
this._app.trigger('clipboard_blur');
},
});
// Expose the grabber as a global to allow upload from tests to explicitly restore focus
window.gristClipboardGrabFocus = () => FocusLayer.grabFocus();
// Some bugs may prevent Clipboard from re-grabbing focus. To limit the impact of such bugs on
// the user, recover from a bad state in mousedown events. (At the moment of this comment, all
// such known bugs are fixed.)
this.onEvent(window, 'mousedown', (ev) => {
if (!document.activeElement || document.activeElement === document.body) {
FocusLayer.grabFocus();
}
});
// In the event of a cut a callback is provided by the viewsection that is the target of the cut.
// When called it returns the additional removal action needed for a cut.
this._cutCallback = null;
// The plaintext content of the cut callback. Used to verify that we are pasting the results
// of the cut, rather than new data from outside.
this._cutData = null;
}
Base.setBaseFor(Clipboard);
/**
* Internal helper fired on `copy` events. If a callback was registered from a component, calls the
* callback to get selection data and puts it on the clipboard.
*/
Clipboard.prototype._onCopy = function(elem, event) {
event.preventDefault();
let pasteObj = commands.allCommands.copy.run();
this._setCBdata(pasteObj, event.originalEvent.clipboardData);
};
Clipboard.prototype._onCut = function(elem, event) {
event.preventDefault();
let pasteObj = commands.allCommands.cut.run();
this._setCBdata(pasteObj, event.originalEvent.clipboardData);
};
Clipboard.prototype._setCBdata = function(pasteObj, clipboardData) {
if (!pasteObj) {
return;
}
let plainText = tableUtil.makePasteText(pasteObj.data, pasteObj.selection);
clipboardData.setData('text/plain', plainText);
let htmlText = tableUtil.makePasteHtml(pasteObj.data, pasteObj.selection);
clipboardData.setData('text/html', htmlText);
if (pasteObj.cutCallback) {
this._cutCallback = pasteObj.cutCallback;
this._cutData = plainText;
} else {
this._cutCallback = null;
this._cutData = null;
}
};
/**
* Internal helper fired on `paste` events. If a callback was registered from a component, calls the
* callback with data from the clipboard.
*/
Clipboard.prototype._onPaste = function(elem, event) {
event.preventDefault();
let cb = event.originalEvent.clipboardData;
let plainText = cb.getData('text/plain');
let htmlText = cb.getData('text/html');
let data;
// Grist stores both text/html and text/plain when copying data. When pasting back, we first
// check if text/html exists (should exist for Grist and other spreadsheet software), and fall
// back to text/plain otherwise.
try {
data = tableUtil.parsePasteHtml(htmlText);
} catch (e) {
if (plainText === '' || plainText.charCodeAt(0) === 0xFEFF) {
data = [['']];
} else {
data = tsvDecode(plainText.replace(/\r\n?/g, "\n"));
}
}
if (this._cutData === plainText) {
if (this._cutCallback) {
// Cuts should only be possible on the first paste after a cut and only if the data being
// pasted matches the data that was cut.
commands.allCommands.paste.run(data, this._cutCallback);
}
} else {
this._cutData = null;
commands.allCommands.paste.run(data, null);
}
// The cut callback should only be usable once so it needs to be cleared after every paste.
this._cutCallback = null;
};
var FOCUS_TARGET_TAGS = {
'INPUT': true,
'TEXTAREA': true,
'SELECT': true,
'IFRAME': true,
};
/**
* Helper to determine if the currently active element deserves to keep its own focus, and capture
* copy-paste events. Besides inputs and textareas, any element can be marked to be a valid
* copy-paste target by adding 'clipboard_focus' class to it.
*/
function allowFocus(elem) {
return elem && (FOCUS_TARGET_TAGS.hasOwnProperty(elem.tagName) ||
elem.hasAttribute("tabindex") ||
elem.classList.contains('clipboard_focus'));
}
Clipboard.allowFocus = allowFocus;
module.exports = Clipboard;