vue-router what is the difference to from :to - vue.js

When to use vue-router link as
<router-link to="/login">Login</router-link> it render to login view and <router-link :to="/login">Login</router-link> this one is the same.
What is the difference and why we use the colon and we must use it ?

The : is v-bind Shorthand syntax.
https://v2.vuejs.org/v2/guide/syntax.html#v-bind-Shorthand
If you want to use Javascript expressions then need to use :
let LoginUrl = '/login'
<router-link :to="loginUrl">Login</router-link>
// Another example
let student = {id: 521, name: 'Jhon Doe'}
<router-link :to="`students/${student.id}`"></router-link>
Without : You're just writing string inside to=""

Colon is shorthand for v-bind directive and you would use it to bind to computed property or method.
https://v2.vuejs.org/v2/guide/syntax.html#v-bind-Shorthand
Examples:
<!-- Static value -->
<router-link to="/login">Login</router-link>
<!-- Dynamic values-->
<router-link :to="`/user/${id}`">Login</router-link>
<router-link :to="getUserLink(id)">Login</router-link>
<router-link :to="currentUserLink">Login</router-link>
new Vue({
data() {
return {
id: 1
}
},
computed: {
currentUserLink() { return '/user/'+ this.id }
},
methods: {
getUserLink(id) {
return '/user/'+ id
}
}
});

Related

regex for router links

I'm trying to build a navbar and since it will receive the links from a prop so it might be a router link or hyperlink which is why I want to use regex to check if the first character is / and if so then use push or else use href. however I'm getting one error. what am I doing wrong here? is my regex wrong? also is my approach correct?
error Unnecessary escape character: \/ no-useless-escape
my code so far
<template>
<nav>
<ul>
<li v-for="(item, $index) in navLinks" :key="$index">
<router-link :to="item.link" v-if="item.link.match(reg)">{{ item.name }}</router-link>
<a :href="item.link" v-else>{{ item.name }}</a>
</li>
</ul>
</nav>
</template>
<script>
export default {
name: "Navbar",
props: {
navLinks: {
type: Array,
},
data () {
return {
reg: '^[\/].*' // the regex which sees if the first character is `/` or not
}
}
}
</script>
the navlinks can be
const navLinks = [
{ name: "About",
link: "#about" },
{
name: "Projects",
link: "/projects",
},
];
In vue, if you want to use a variable in the template section then you need to define it inside the data property.
data () {
return {
reg: '^[/].*'
}
}
Now you can access this reg in the template section.
For the issue of the regular expression, define your regex as '^[/].*'.

wrap template component with his name

I have components and I would like every component template wrapped inside a div with his name.
Vue.component('search', {
template: '<div>component template</div>'
html result
<div class="component-search">
<div>component template</div>
</div>
I can't imagine why you would want to be do that but anyhow you could do the following
Vue.component('search', {
name: 'search',
template: `<div :class="wrapperClass">
<div>component template</div>
</div>`,
computed: {
componentName() {
return this.$options.name
},
wrapperClass() {
return `component-${this.componentName}`
},
}
})

Conditional link behavior in VueJS

Couldn't find a proper name for the title, will be glad if someone figures out a better name.
I have a component which represents a product card. The whole component is wrapped in <router-link> which leads to product page.
However I have another case, when I do not need the component to lead to a product page, but instead I need to do some other action.
The only solution I found is to pass a callback function as a prop, and based on this, do something like:
<router-link v-if="!onClickCallback">
... here goes the whole component template ...
</router-link>
<div v-if="onClickCallback" #click="onClickCallback">
... here again goes the whole component template ...
</div>
How can I do this without copy-pasting the whole component? I tried to do this (real code sample):
<router-link class="clothing-item-card-preview"
:class="classes"
:style="previewStyle"
:to="{ name: 'clothingItem', params: { id: this.clothingItem.id }}"
v-on="{ click: onClick ? onClick : null }">
However I got this: Invalid handler for event "click": got null
Plus not sure if it's possible to pass prevent modificator for click and this just looks weird, there should be a better architectural solution
Commenting on the error, you could use an empty function instead of null, in the real code snippet
<router-link class="clothing-item-card-preview"
:class="classes"
:style="previewStyle"
:to="{ name: 'clothingItem', params: { id: this.clothingItem.id }}"
v-on="{ click: onClick ? onClick : null }">
This should works (replace a for "router-link" then insert right properties)
Further infos :
https://fr.vuejs.org/v2/guide/components-dynamic-async.html
v-bind is simply an Object where each keys is a props for your component, so here, I programmatically defined an object of properties depending on the wrapper (router link or a simple div). However we cannot do this for events (of course we could create our own event listener but it's a little bit tricky) so I simply but an handle method.
new Vue({
el: "#app",
data: {
products : [{onClickCallback : () => { alert("callback"); return true;}}, {}, {}]
},
methods : {
handleClick(product, event) {
if (!product.onClickCallback) return false
product.onClickCallback()
return true
},
getMyComponentName(product) {
if (product.onClickCallback) return "div"
return "a"
},
getMyComponentProperties(product) {
if (product.onClickCallback) return {is : "div"}
return {
is : "a",
href: "!#"
}
}
}
})
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
<div id="app">
<component
v-for="(product, index) in products"
:key="index"
v-bind="getMyComponentProperties(product)"
#click="handleClick(product, $event)"
>
<div class="product-card">
<div class="product-card-content">
<span v-show="product.onClickCallback">I'm a callback</span>
<span v-show="!product.onClickCallback">I'm a router link</span>
</div>
</div>
</component>
</div>
Do you have to use a <router-link>? If it can safely be a <div>, you could use something like
<div #click="handleClick" ...>
<!-- component template -->
</div>
and
methods: {
handleClick (event) {
if (this.onClickCallback) {
this.onClickCallback(event)
} else {
this.$router.push({ name: 'clothingItem', ... })
}
}
}
See https://router.vuejs.org/guide/essentials/navigation.html

How can I add operator ternary in input type text on vue.js 2?

My vue component like this :
<template>
<div>
...
<li v-for="category in categories">
...
<input type="radio" class="category-radio" :value="category.id" (category.id == categoryId) ? 'checked data-waschecked=true' : ''>
...
</li>
...
</div>
</template>
<script>
export default {
props: ['categories', 'categoryId'],
}
</script>
I want to add condition in input type text. I use operator ternary like above code
If the code executed, it does not work
There is no error. So i'm confused to solve it
Maybe my code is still not correct
How can I solve it?
The issue is you're trying to use JavaScript expression inside plain HTML. This won't work.
You can either bind each attribute manually like this:
:checked="(expression) ? true : false"
or bind to a computed property which depends on your expression and returns your calculated property. Alternatively, you can bind an object with one to many properties, and bind the whole object at once (this is possible also):
new Vue({
el: '#app',
data: {
categories: [
{ id: 1, name: 'one' },
{ id: 2, name: 'two' },
{ id: 3, name: 'three' }
],
selectedId: 2 // for simplicity
},
computed: {
attrs: function() {
return function(id) { // computed can also return a function, so you can use args
return (id === this.selectedId) ? { checked: true, 'data-waschecked': true } : {}
}
}
},
mounted() { // log your element
console.log(document.querySelector('input[data-waschecked=true]'))
}
});
<script src="https://unpkg.com/vue/dist/vue.js"></script>
<div id="app">
<ul>
<li v-for="category in categories">
<input type="checkbox" v-bind="attrs(category.id)">
</li>
</ul>
</div>

Conditional <router-link> in Vue.js dependant on prop value?

Hopefully this is a rather simple question / answer, but I can't find much info in the docs.
Is there a way to enable or disable the anchor generated by <router-link> dependent on whether a prop is passed in or not?
<router-link class="Card__link" :to="{ name: 'Property', params: { id: id }}">
<h1 class="Card__title">{{ title }}</h1>
<p class="Card__description">{{ description }}</p>
</router-link>
If there's no id passed to this component, I'd like to disable any link being generated.
Is there a way to do this without doubling up the content into a v-if?
Thanks!
Assuming you want to disable anchor tag as in not clickable and look disabled the option is using CSS. isActive should return true by checking prop id.
<router-link class="Card__link" v-bind:class="{ disabled: isActive }" :to="{ name: 'Property', params: { id: id }}">
<h1 class="Card__title">{{ title }}</h1>
<p class="Card__description">{{ description }}</p>
</router-link>
<style>
.disabled {
pointer-events:none;
opacity:0.6;
}
<style>
If you want to just disable the navigation , you can use a route guard.
beforeEnter: (to, from, next) => {
next(false);
}
If you need to use it often, consider this:
Create new component
<template>
<router-link
v-if="!disabled"
v-bind="$attrs"
>
<slot/>
</router-link>
<span
v-else
v-bind="$attrs"
>
<slot/>
</span>
</template>
<script>
export default {
name: 'optional-router-link',
props: {
params: Object,
disabled: {
type: Boolean,
default: false,
},
},
};
</script>
Optional, register globally:
Vue.component('optional-router-link', OptionalRouterLink);
Use it as follows:
<optional-router-link
:disabled="isDisabled"
:to="whatever"
>
My link
</optional-router-link>
The problem is that router-link renders as an html anchor tag, and anchor tags do not support the disabled attribute. However you can add tag="button" to router-link:
<router-link :to="myLink" tag="button" :disabled="isDisabled" >
Vue will then render your link as a button, which naturally supports the disabled attribute. Problem solved! The downside is that you have to provide additional styling to make it look like a link. However this is the best way to achieve this functionality and does not rely on any pointer-events hack.
I sometimes do stuff like this:
<component
:is="hasSubLinks ? 'button' : 'router-link'"
:to="hasSubLinks ? undefined : href"
:some-prop="computedValue"
#click="hasSubLinks ? handleClick() : navigate"
>
<!-- arbitrary markup -->
</component>
...
computed: {
computedValue() {
if (this.hasSubLinks) return 'something';
if (this.day === 'Friday') return 'tgif';
return 'its-fine';
},
},
But I basically always wrap router-link, so you can gain control over disabled state, or pre-examine any state or props before rendering the link, with something like this:
<template>
<router-link
v-slot="{ href, route, navigate, isActive, isExactActive }"
:to="to"
>
<a
:class="['nav-link-white', {
'nav-link-white-active': isActive,
'opacity-50': isDisabled,
}]"
:href="isDisabled ? undefined : href"
#click="handler => handleClick(handler, navigate)"
>
<slot></slot>
</a>
</router-link>
</template>
<script>
export default {
name: 'top-nav-link',
props: {
isDisabled: {
type: Boolean,
required: false,
default: () => false,
},
to: {
type: Object,
required: true,
},
},
data() {
return {};
},
computed: {},
methods: {
handleClick(handler, navigate) {
if (this.isDisabled) return undefined;
return navigate(handler);
},
},
};
</script>
In my app right now, I'm noticing that some combinations of #click="handler => handleClick(handler, navigate)" suffer significantly in performance.
For example this changes routes very slow:
#click="isDisabled ? undefined : handler => navigate(handler)"
But the pattern in my full example code above works and has no performance issue.
In general, ternary operator in #click can be very dicey, so if you get issues, don't give up right away, try many different ways to bifurcate on predicates or switch over <component :is="" based on state. navigate itself is an ornery one because it requires the implicit first parameter to work.
I haven't tried, but you should be able to use something like Function.prototype.call(), Function.prototype.apply(), or Function.prototype.bind().
For example, you might be able to do:
#click="handler => setupNavigationTarget(handler, navigate)"
...
setupNavigationTarget(handler, cb) {
if (this.isDisabled) return undefined;
return this.$root.$emit('some-event', cb.bind(this, handler));
},
...
// another component
mounted() {
this.$root.$on('some-event', (navigate) => {
if (['Saturday', 'Sunday'].includes(currentDayOfTheWeek)) {
// halt the navigation event
return undefined;
}
// otherwise continue (and notice how downstream logic
// no longer has to care about the bound handler object)
return navigate();
});
},
You could also use the following:
<router-link class="Card__link" :to="id ? { name: 'Property', params: { id: id }} : {}">
<h1 class="Card__title">{{ title }}</h1>
<p class="Card__description">{{ description }}</p>
</router-link>
If id is undefined the router won't redirect the page to the link.
I've tried different solutions but only one worked for me, maybe because I'm running if from Nuxt? Although theoretically nuxt-link should work exactly the same as router-link.
Anyway, here is the solution:
<template>
<router-link
v-slot="{ navigate }"
custom
:to="to"
>
<button
role="link"
#click="onNavigation(navigate, $event)"
>
<slot></slot>
</button>
</router-link>
</template>
<script>
export default {
name: 'componentName',
props: {
to: {
type: String,
required: true,
},
},
methods: {
onNavigation(navigate, event) {
if (this.to === '#other-action') {
// do something
} else {
navigate(event);
}
return false;
},
};
</script>