I want to add two numbers in vue
data() {
return {
details: {
num1: 100,
num2: 500,
total: num1 + num2
}
}
}
Is this not possible and bad practice? I can create a computed but this as a temp shortcut would be useful. Is it just the scope I have wrong?
It's a very bad practice!
In Vue.js you should always use computed properties for any calculation.
But in your case you should do something like this:
<template>
<div>{{details.total()}}</div>
</template>
<script>
export default {
data() {
return {
details: {
num1: 100,
num2: 500,
total: () => this.details.num1 + this.details.num2
}
}
}
}
}
</script>
Related
Let's suppose I have this simple code:
const a = {
number: 2,
method() {
return this.number
}
}
console.log(a.method()) // prints 2
Now I'd like to reimplement method in terms of method itself. Ideally:
a.method = function() {
return 40 + this.method() // should print 42, get a RangeError: Maximum call stack size exceeded
}
Is there a way to achieve this?
You could try something like this:
const a = {
number: 2,
method() {
return this.number
}
}
// 1. Store old method
var oldMethod = a.method.bind(a)
// 2. Reference old method in new declaration
a.method = function() {
return 40 + oldMethod()
}
console.log(a.method())
See MDN for more info on .bind.
macro_rules! retry_put {
($mod_name:ident, $data_type:ty) => {{
fn $mod_name() {
// somelike
if $mod_name == "red" {
// generate code written here and not the one in else block
return u8;
}
else {
// generate code written here and not the one in if
return "string";
}
}
}
}
I am tring to change the return type based on input basically, if input is true return string else return int.
Or maybe give example for :
give example where we are accepting a arguement in macro and if its even calulate factorial of 5 and return it as integer and if the agruement is odd calculate the factoreial of 5 and return it as string. And name of both functions should be same. and logic of calculating 5! should not be repeated.
You can overload a macro like this:
macro_rules! retry_put {
(red, $data_type:ty) => {{
fn red() {
return u8;
}
}
}
($mod_name:ident, $data_type:ty) => {{
fn $mod_name() {
return "string";
}
}
}
}
See macro_rules!.
I am trying to remove rows inside a ForEach. Removing the last row always throws an index out of range exception. Removing any other row does not.
ForEach(Array(player.scores.enumerated()), id: \.element) { index, score in
HStack {
if self.isEditSelected {
Button(action: {
self.player.scores.remove(at: index)
}, label: {
Image("delete")
})
}
TextField("\(score)", value: self.$player.scores[index], formatter: NumberFormatter())
}
}
I have tried using ForEach(player.indices...) & ForEach(player.scores...), but see the same problem.
Looks to me like the crash happens here self.$player.scores[index], as hardcoding the index to any value other that the last row is working.
Does anyone know how to fix this? Or if there is a better approach.
Here is fix
ForEach(Array(player.scores.enumerated()), id: \.element) { index, score in
HStack {
if self.isEditSelected {
Button(action: {
self.player.scores.remove(at: index)
}, label: {
Image("delete")
})
}
TextField("\(score)", value: Binding( // << use proxy binding !!
get: { self.player.scores[index] },
set: { self.player.scores[index] = $0 }),
formatter: NumberFormatter())
}
}
Based on #Asperi answer
public extension Binding where Value: Equatable {
static func proxy(_ source: Binding<Value>) -> Binding<Value> {
self.init(
get: { source.wrappedValue },
set: { source.wrappedValue = $0 }
)
}
}
You can use this as follows:
TextField("Name", text: .proxy($variable))
Xcode 13.0 beta introduced a new way to establish two-way-bindings between the elements of a collection and the views built by ForEach / List.
This method fixes the crash related to deleting the last row.
struct Score: Identifiable {
let id = UUID()
var value: Int
}
struct Player {
var scores: [Score] = (1...10).map {_ in .init(value: Int.random(in: 0...25))}
}
struct BindingTest: View {
#State private var player = Player()
var body: some View {
List {
ForEach($player.scores) { $score in
HStack {
TextField("\(score.value)", value: $score.value,
formatter: NumberFormatter())
}
}
.onDelete { player.scores.remove(atOffsets: $0)}
}
}
}
I have a website where I can upload a .xlsx file which contains some rows of information for my database. I read the documentation for laravel-excel but it looks like it only works with progress bar if you use the console method; which I don't.
I currently just use a plain HTML upload form, no ajax yet.
But to create this progress bar for this I need to convert it to ajax, which is no hassle, that I can do.
But how would I create the progress bar when uploading the file and iterating through each row in the Excel file?
This is the controller and method where the upload gets done:
/**
* Import companies
*
* #param Import $request
* #return \Illuminate\Routing\Redirector|\Illuminate\Http\RedirectResponse
*/
public function postImport(Import $request)
{
# Import using Import class
Excel::import(new CompaniesImport, $request->file('file'));
return redirect(route('dashboard.companies.index.get'))->with('success', 'Import successfull!');
}
And this is the import file:
public function model(array $row)
{
# Don't create or validate on empty rows
# Bad workaround
# TODO: better solution
if (!array_filter($row)) {
return null;
}
# Create company
$company = new Company;
$company->crn = $row['crn'];
$company->name = $row['name'];
$company->email = $row['email'];
$company->phone = $row['phone'];
$company->website = (!empty($row['website'])) ? Helper::addScheme($row['website']) : '';
$company->save();
# Everything empty.. delete address
if (!empty($row['country']) || !empty($row['state']) || !empty($row['postal']) || !empty($row['address']) || !empty($row['zip'])) {
# Create address
$address = new CompanyAddress;
$address->company_id = $company->id;
$address->country = $row['country'];
$address->state = $row['state'];
$address->postal = $row['postal'];
$address->address = $row['address'];
$address->zip = $row['zip'];
$address->save();
# Attach
$company->addresses()->save($address);
}
return $company;
}
I know this is not much at this point. I just need some help figuring out how I would create this progress bar, because I'm pretty stuck.
My thought is to create a ajax upload form though, but from there I don't know.
Just an idea, but you could use the Laravel session to store the total_row_count and processed_row_count during the import execution. Then, you could create a separate AJAX call on a setInterval() to poll those session values (e.g., once per second). This would allow you to calculate your progress as processed_row_count / total_row_count, and output to a visual progress bar. – matticustard
Putting #matticustard comment into practice. Below is just sample of how things could be implemented, and maybe there are areas to improve.
1. Routes
import route to initialize Excel import.
import-status route will be used to get latest import status
Route::post('import', [ProductController::class, 'import']);
Route::get('import-status', [ProductController::class, 'status']);
2. Controller
import action will validate uploaded file, and pass $id to ProductsImport class. As it will be queued and run in the background, there is no access to current session. We will use cache in the background. It will be good idea to generate more randomized $id if more concurrent imports will be processed, for now just unix date to keep simple.
You currently cannot queue xls imports. PhpSpreadsheet's Xls reader contains some non-utf8 characters, which makes it impossible to queue.
XLS imports could not be queued
public function import()
{
request()->validate([
'file' => ['required', 'mimes:xlsx'],
]);
$id = now()->unix()
session([ 'import' => $id ]);
Excel::queueImport(new ProductsImport($id), request()->file('file')->store('temp'));
return redirect()->back();
}
Get latest import status from cache, passing $id from session.
public function status()
{
$id = session('import');
return response([
'started' => filled(cache("start_date_$id")),
'finished' => filled(cache("end_date_$id")),
'current_row' => (int) cache("current_row_$id"),
'total_rows' => (int) cache("total_rows_$id"),
]);
}
3. Import class
Using WithEvents BeforeImport we set total rows of our excel file to the cache. Using onRow we set currently processing row to the cache. And AfterReset clear all the data.
<?php
namespace App\Imports;
use App\Models\Product;
use Maatwebsite\Excel\Row;
use Maatwebsite\Excel\Concerns\OnEachRow;
use Maatwebsite\Excel\Events\AfterImport;
use Maatwebsite\Excel\Events\BeforeImport;
use Maatwebsite\Excel\Concerns\WithEvents;
use Illuminate\Contracts\Queue\ShouldQueue;
use Maatwebsite\Excel\Concerns\WithStartRow;
use Maatwebsite\Excel\Concerns\WithChunkReading;
use Maatwebsite\Excel\Concerns\WithMultipleSheets;
class ProductsImport implements OnEachRow, WithEvents, WithChunkReading, ShouldQueue
{
public $id;
public function __construct(int $id)
{
$this->id = $id;
}
public function chunkSize(): int
{
return 100;
}
public function registerEvents(): array
{
return [
BeforeImport::class => function (BeforeImport $event) {
$totalRows = $event->getReader()->getTotalRows();
if (filled($totalRows)) {
cache()->forever("total_rows_{$this->id}", array_values($totalRows)[0]);
cache()->forever("start_date_{$this->id}", now()->unix());
}
},
AfterImport::class => function (AfterImport $event) {
cache(["end_date_{$this->id}" => now()], now()->addMinute());
cache()->forget("total_rows_{$this->id}");
cache()->forget("start_date_{$this->id}");
cache()->forget("current_row_{$this->id}");
},
];
}
public function onRow(Row $row)
{
$rowIndex = $row->getIndex();
$row = array_map('trim', $row->toArray());
cache()->forever("current_row_{$this->id}", $rowIndex);
// sleep(0.2);
Product::create([ ... ]);
}
}
4. Front end
On the front-end side this is just sample how things could be handled. Here I used vuejs, ant-design-vue and lodash.
After uploading file handleChange method is called
On successful upload trackProgress method is called for the first time
trackProgress method is recursive function, calling itself on complete
with lodash _.debounce method we can prevent calling it too much
export default {
data() {
this.trackProgress = _.debounce(this.trackProgress, 1000);
return {
visible: true,
current_row: 0,
total_rows: 0,
progress: 0,
};
},
methods: {
handleChange(info) {
const status = info.file.status;
if (status === "done") {
this.trackProgress();
} else if (status === "error") {
this.$message.error(_.get(info, 'file.response.errors.file.0', `${info.file.name} file upload failed.`));
}
},
async trackProgress() {
const { data } = await axios.get('/import-status');
if (data.finished) {
this.current_row = this.total_rows
this.progress = 100
return;
};
this.total_rows = data.total_rows;
this.current_row = data.current_row;
this.progress = Math.ceil(data.current_row / data.total_rows * 100);
this.trackProgress();
},
close() {
if (this.progress > 0 && this.progress < 100) {
if (confirm('Do you want to close')) {
this.$emit('close')
window.location.reload()
}
} else {
this.$emit('close')
window.location.reload()
}
}
},
};
<template>
<a-modal
title="Upload excel"
v-model="visible"
cancel-text="Close"
ok-text="Confirm"
:closable="false"
:maskClosable="false"
destroyOnClose
>
<a-upload-dragger
name="file"
:multiple="false"
:showUploadList="false"
:action="`/import`"
#change="handleChange"
>
<p class="ant-upload-drag-icon">
<a-icon type="inbox" />
</p>
<p class="ant-upload-text">Click to upload</p>
</a-upload-dragger>
<a-progress class="mt-5" :percent="progress" :show-info="false" />
<div class="text-right mt-1">{{ this.current_row }} / {{ this.total_rows }}</div>
<template slot="footer">
<a-button #click="close">Close</a-button>
</template>
</a-modal>
</template>
<script>
export default {
data() {
this.trackProgress = _.debounce(this.trackProgress, 1000);
return {
visible: true,
current_row: 0,
total_rows: 0,
progress: 0,
};
},
methods: {
handleChange(info) {
const status = info.file.status;
if (status === "done") {
this.trackProgress();
} else if (status === "error") {
this.$message.error(_.get(info, 'file.response.errors.file.0', `${info.file.name} file upload failed.`));
}
},
async trackProgress() {
const { data } = await axios.get('/import-status');
if (data.finished) {
this.current_row = this.total_rows
this.progress = 100
return;
};
this.total_rows = data.total_rows;
this.current_row = data.current_row;
this.progress = Math.ceil(data.current_row / data.total_rows * 100);
this.trackProgress();
},
close() {
if (this.progress > 0 && this.progress < 100) {
if (confirm('Do you want to close')) {
this.$emit('close')
window.location.reload()
}
} else {
this.$emit('close')
window.location.reload()
}
}
},
};
</script>
I'm writing a simple React application with a Button component, which looks like this:
import React, { Component } from 'react';
// shim to find stuff
Array.prototype.contains = function (needle) {
for (var i = 0; i < this.length; i++) {
if (this[i] == needle) return true;
}
return false;
};
class Button extends Component {
propTypes: {
text: React.PropTypes.string.isRequired,
modifiers: React.PropTypes.array
}
render() {
return(
<span className={this.displayModifiers()}>{this.props.text}</span>
);
}
displayModifiers() {
const modifiers = this.props.modifiers || ["default"];
if (modifiers.contains("default") ||
modifiers.contains("danger") ||
modifiers.contains("success")) {
// do nothing
} else {
// add default
modifiers.push("defualt");
}
var classNames = "btn"
for (var i = 0; i < modifiers.length; i++) {
classNames += " btn-" + modifiers[i]
}
return(classNames);
}
}
export default Button;
I then wrote this to test it:
it("contains the correct bootstrap classes", () => {
expect(mount(<Button modifiers={["flat"]}/>).html()).toContain("<span class=\"btn btn-flat btn-default\"></span>");
});
That code should pass, but I receive the following error message:
expect(string).toContain(value)
Expected string:
"<span class=\"btn btn-flat btn-defualt\"></span>"
To contain value:
"<span class=\"btn btn-flat btn-default\"></span>"
at Object.it (src\__tests__\Button.test.js:42:293)
Any ideas why this is not passing?
From the docs:
Use .toContain when you want to check that an item is in a list.
To test strings you should use toBe or toEqual
it("contains the correct bootstrap classes", () => {
expect(mount(<Button modifiers={["flat"]}/>).html()).toBe("<span class=\"btn btn-flat btn-default\"></span>");
});
But there is a better way of testing the output rendered components: snapshots.
it("contains the correct bootstrap classes", () => {
expect(mount(<Button modifiers={["flat"]}/>).html()).toMatchSnapshot();
});
Note that you will need enzymeToJson for snapshot testing using enzyme.