My code is as follows:
https://jsfiddle.net/2g7m5qy5/139/
The initial dummy buttons are disabled. When the input value changes, the 'Dummy' button is enabled.
Suppose I have the following sequence of events:
I change 'a' to 'abc'
The 'Dummy' button is then enabled
I press 'Submit' in the top row
The 'Dummy' button is still enabled
In the top row, I press space then backspace, so that the input is still 'abc'
Note now that the 'Dummy' button is disabled
What I really want is for the Dummy button to be disabled at step (4) above, straight after 'Submit' is pressed.
For some reason, no change is firing after this line of code:
that.initialValues[index] = value;
How do I get my 'Dummy' button to be disabled straight after 'Submit' is pressed?
This issue is about reactivity.
Changing an element from your array will not make the computed based on this array re-render.
You have multiple options here :
Re-assign the array
In your submit method, you can create a copy of the array, change the element and then re-assign the array in your Vue instance :
submit: function(value, index) {
setTimeout(() => {
const initialValues = [ ...this.initialValues ]
initialValues[index] = value;
this.initialValues = initialValues
}, 100);
}
Using $set
You can also use the $set method to set your new value and make the computed re-render :
submit: function(value, index) {
setTimeout(() => {
this.$set(this.initialValues, index, value)
}, 100);
}
Related
I have a table in my Vuejs project similar to the one that I shared its screenshot above.
My question is; How can I delete a <tr> element from the table when the Delete button of it is pressed for each row?
On the other hand, I want the Add button at the top right of the table to be functional as well. When I click the Add button, I want another <tr> element to be created at the bottom of the table. However, there should be input fields on this element where the user can enter information for each column. After the user has written the information in each column, that row should be added to the table. How can I do that?
if I am correct you are using v-for loop to render all <tr>s
then use the v-for with index like v-for="(obj, index) in objects" to obtain index
to add use Array.prototype.push() to add empty row e.g. objects.push({x: null, y: null})
to remove use Array.prototype.splice() e.g objects.splice(index, 1)
just assign those functionalities to respective buttons.
You could attempt this using a data property in your component and then implement two methods: deleteRow and addRow.
This could be an example code
data() {
return {
dataTable: [
{
id: 1,
code: code1,
description: description1,
},
{
id: 2,
code: code2,
description: description3,
},
...
]
}
}
methods: {
deleteRow(id) {
this.dataTable = this.dataTable.splice(
this.dataTable.findIndex(item => item.id === id)
)
}
addRow(newRow) {
// newRow = {id: 3, code: code3, description: description3}
this.dataTable = [...this.dataTable, newRow]
}
},
Your component will be updated by Vue.js reactivity system.
Probably addRow method should be called from a modal component where you put the input fields to set newRow.
I use vue-chartjs to draw some chart like line, bar, etc.
In my project, there are many cases using specific value or lable of data in chart.
Using tooltip option of vue-chartjs, I can check that value or label of data item when hovered.
I want to know how to access or get information of specific data matched with point on graph when clicked(not hovered).
Here is my code about chart options.
chartOptions: {
responsive: false,
onClick: function(evt){
//Some logic to get value of label of specific data...(type, label, value, ...)
}
In my case, I use 'onclick' option to access specific data on point triggered 'click' event. In 'onClick' callback, I checked all of chart elements and dataset, etc.
How can I get value of label specific dataItem on point of graph(like line) or bar of graph(like bar) when triggered click event?
I was not able to find a solution that worked for me, but I dug a little bit and this is what I came up with.
onClick: function(evt, array) {
if (array.length != 0) {
var position = array[0]._index;
var activeElement = this.tooltip._data.datasets[0].data[position]
console.log(activeElement);
} else {
console.log("You selected the background!");
}
}
This will get the position in the array that you clicked and grab the data from what position you clicked. This may not be the prettiest or best example, but it worked for me.
This solution use the getElementAtEvent method of chartjs, but to use that you need reference to the Chart itself, not the Vue component. We can get that from the $data._chart property. To use this in a parent Vue component, we use the $refs as seen below`.
So parent defines the chart options
{
...
options: {
onClick: this.handleChartClick
}
...
}
and then parent method, using $refs with $data._chart to get the chart. We get the datasetIndex and value and also the tooltip
handleChartClick(evt, elements) {
var chart = this.$refs.periodChart.$data._chart;
const chartIndex = chart.getElementAtEvent(evt);
if (chartIndex.length !== 0) {
const datasetIndex = chartIndex[0]._datasetIndex;
const position = chartIndex[0]._index;
const info = {
datasetIndex: datasetIndex,
valueIndex: position,
label: chart.tooltip._data.labels[position],
value: chart.tooltip._data.datasets[datasetIndex].data[position]
};
console.log(info);
} else {
console.log("Background clicked");
}
I have a vaadin-checkbox:
<vaadin-checkbox id=[[item.id]] disabled="true" checked="[[item.checked]]">[[item.description]]</vaadin-checkbox>
I defined my properties:
static get properties() {
return {
items: {
type: Array,
notify: true,
value: function() {
return [];
}
}
};
}
When I now change the data by pressing some button:
_selectItem(event) {
const item = event.model.item;
if (item.checked === true) {
this.$.grid.deselectItem(item);
} else {
this.$.grid.selectItem(item);
}
item.checked = !item.checked;
}
The state of the checkbox is still checked="true". Why isnt the checkbox getting updated? The same thing when I change the description of the item:
_selectItem(event) {
event.model.item.description = 'test';
}
The test description is never appearing. The checkbox is never getting updated.
The reason why the checkbox does not get updated by the button click handler is in the Polymer 2 data system. Polymer does not detect the change and does not update the template accordingly.
In order to make the change in a way that Polymer would detect it you have two options:
Use this.set(`items.${event.model.index}.checked`, !item.checked) if you can reliably assume that the index used by dom-repeat always matches that elements's index in the items array (it is not the case if you use sorting or filtering features of dom-repeat). See an example here https://jsfiddle.net/vlukashov/epd0dn2j/
If you do not know the index of the updated item in the items array, you can also use the Polymer.MutableData mixin and notify Polymer that something has changed inside the items array without specifying the index of the changed item. This is done by calling this.notifyPath('items') after making a change. However, this requires that your element extends the Polymer.MutableData mixin, and that dom-repeat has the mutable-data attribute set. See an example here: https://jsfiddle.net/vlukashov/epd0dn2j/24/
More information on this in the Polymer 2 docs.
I have created a dijit.Tree object where every node is a checkbox. When you select/deselect the parent node, the child nodes get selected/deselected;
when one of the children is deselected, the parent gets deselected; when all the children are selected, the parent gets selected. It works perfectly fine.
However I need it to be keyboard accessible. When I navigate to the tree nodes and press spacebar or Enter, nothing happens.
I tried adding tabindex and aria-role to the checkbox (programmatically), but it did not work.
Here is the fiddle - http://jsfiddle.net/pdabade/pyz9Lcpv/65/
require([
"dojo/_base/window", "dojo/store/Memory",
"dijit/tree/ObjectStoreModel",
"dijit/Tree", "dijit/form/CheckBox", "dojo/dom",
"dojo/domReady!"
], function(win, Memory, ObjectStoreModel, Tree, checkBox, dom) {
// Create test store, adding the getChildren() method required by ObjectStoreModel
var myStore = new Memory({
data: [{
id: 'allDocuments',
name: 'All Documents'
}, {
id: 'inboxDocuments',
name: 'Inbox Documents',
parent: 'allDocuments'
}, {
id: 'outboxDocuments',
name: 'Outbox Documents',
parent: 'allDocuments'
}, {
id: 'draftDocuments',
name: 'Draft Documents',
parent: 'allDocuments'
}, {
id: 'finalDocuments',
name: 'Final Documents',
parent: 'allDocuments'
}],
getChildren: function(object) {
return this.query({
parent: object.id
});
}
});
// Create the model
var myModel = new ObjectStoreModel({
store: myStore,
query: {
id: 'allDocuments'
}
});
// Create the Tree.
var tree = new Tree({
model: myModel,
autoExpand: true,
getIconClass: function(item, opened) {
// console.log('tree getIconClass', item, opened);
// console.log('tree item type', item.id);
},
onClick: function(item, node, event) {
//node._iconClass= "dijitFolderClosed";
//node.iconNode.className = "dijitFolderClosed";
var _this = this;
console.log(item.id);
var id = node.domNode.id,
isNodeSelected = node.checkBox.get('checked');
dojo.query('#' + id + ' .dijitCheckBox').forEach(function(node) {
dijit.getEnclosingWidget(node).set('checked', isNodeSelected);
});
if (item.id != 'allComments') {
if (!isNodeSelected) {
var parent = node.tree.rootNode; // parent node id
//console.log(node);
parent.checkBox.set('checked', false);
} else {
var parent = node.tree.rootNode;
var selected = true;
var i = 0;
dojo.query('#' + parent.id + '.dijitCheckBox').forEach(function(node) {
if (i > 0) {
var isSet = dijit.getEnclosingWidget(node).get('checked');
console.log(isSet);
if (isSet == false) {
selected = false;
}
}
i++;
});
if (selected) {
parent.checkBox.set('checked', true);
}
}
}
//console.log(node.id);
},
_createTreeNode: function(args) {
var tnode = new dijit._TreeNode(args);
tnode.labelNode.innerHTML = args.label;
console.log(args);
var cb = new dijit.form.CheckBox({
"aria-checked": "false",
"aria-describedby": args.label
});
cb.placeAt(tnode.labelNode, "first");
tnode.checkBox = cb;
return tnode;
}
});
tree.placeAt(contentHere);
tree.startup();
tree.checkedItems();
//tree.expandAll();
});
}
Any ideas as to how to make it keyboard accessible?
Thanks!
Looking into the dijit/Tree source I see that it sets the function _onNodePress() as an event handler for keyboard events. You can override it (or add an aspect after it) and handle the key presses you want manually. It takes as argument the tree node and an event object that you can use to check specifically for the space and the enter key.
I forked your jsfiddle with an example: https://jsfiddle.net/pgianna/jjore5sm/1/
_onNodePress: function(/*TreeNode*/ nodeWidget, /*Event*/ e){
// This is the original implementation of _onNodePress:
this.focusNode(nodeWidget);
// This requires "dojo/keys"
if (e.keyCode == keys.ENTER || e.keyCode == keys.SPACE)
{
var cb = nodeWidget.checkBox;
cb.set('checked', !cb.get('checked'));
}
}
Do not add role, aria-checked, nor tabindex to the checkbox. Those are already built into the control, so you are adding risk of breaking it down the road. You can probably also get rid of every role="presentation" as those are on <div>s and <span>s which are presentational by nature. Finally, you need <label> on each block of text that is associated with a checkbox if you want this to be accessible. The aria-describedby is incorrect and is the less good option anyway.
I am getting the error: Uncaught TypeError: tree.checkedItems is not a function (line 159)
You also have a big focus management problem. Put the following in your CSS and you will see that it takes two presses of the Tab key for each single control (if starting at a focused checkbox): :focus {outline:2px solid #f00;}
It looks like you have the containing elements stealing any clicks, meaning the correct element never gets selected. The <span> with classes dijit dijitReset dijitInline dijitCheckBox keeps stealing focus as it toggles its tabindex from -1 to 0, taking itself in and out of the tab order. That may be a factor.
I suggest addressing the script error and then looking at focus management.
With dijit, there's all kinds of stuff going on in the background that might be out of your control. As aardrian said, there's lots of role=presentation and all the aria tags on the <input type='checkbox> are superfluous. dijit is probably (incorrectly) setting all that. An <input type='checkbox> already handles selections and it's role is inherently a checkbox. Those aria properties are for when you're making a custom checkbox out of div/span tags.
There is a native checkbox buried down in the code but it has opacity set to 0 so you can't see it. dijit is probably using it for the checkbox events.
The native checkbox also has data-dojo-attach-event="ondijitclick:_onClick". I'm not sure what that means but anytime I see "click" in an event name, I get suspicious that it might not work with a keyboard.
I tried the example on https://dojotoolkit.org/reference-guide/1.10/dijit/form/CheckBox.html and it works with the keyboard. Hit space will check and uncheck the box. Whether you can see the focus on the checkbox is another issue.
As a side note, it might be nice if your checkbox tree used aria-checked="mixed" for the parent branch. Anytime you have child checkboxes where some are selected and some are not, you can use "mixed" for the parent checkbox to indicate a mixture of selections. Not sure if dijit supports that.
I read somewhere, the DOM is updated every time an event occurs and there is changes in data which are bound to DOM. So I wished to learn more about it. I tried the code below but the DOM is not updated when data in textarea changes but its updated whenever I click or press tab key.
var app = {
controller: function () {
var self = this;
this.model = {};
this.model.errors = [];
this.break_data = function (value) {
self.model.errors = value.split(' ');
m.redraw();
}
},
view: function (ctrl) {
return m('.content', [
m('textarea', {onchange: m.withAttr('value', ctrl.break_data)}),
ctrl.model.errors.map(function (error) {
return m('.error', error);
})
]);
}
}
m.mount(document.getElementById('app'), app);
I even tried m.startComputaion(), m.stopComputation() and m.redraw() non of them works.
The redrawing timing is described here: https://stackoverflow.com/a/30728976/70894
As for your example, the problem is not Mithril but the event. You need to use oninput instead of onchange to look for immediate changes. As the Mozilla docs for the "change" event states:
The change event is fired for input, select, and textarea
elements when a change to the element's value is committed by the
user. Unlike the input event, the change event is not necessarily
fired for each change to an element's value.
Here's a fiddle with your code that uses oninput: http://jsfiddle.net/ciscoheat/LuLcra77/
Note that you don't need m.redraw in the event handler anymore now when the correct event is used, since Mithril redraws automatically after every event defined in a call to m().