Vue Error in render: "RangeError: Invalid array length" - vue.js

Vue: v2.*
In my project vuejs
I use v-for range
with computed
Computed
computed: {
numberOfPages() {
const result = Math.ceil(this.collection.total / this.collection.per_page)
return (result < 1) ? 1 : result
}
},
template
<li class="waves-effect" v-for="(number,index) in numberOfPages"
:key="index" :class="collection.current_page == number ? 'active' : ''"
#click="currentPage(number)">
<a class="">{{number}}</a>
</li>
Error Console
1 - [Vue warn]: Error in render: "RangeError: Invalid array length"
2 - RangeError: Invalid array length

The most likely candidate for your problem is that your computed property returns NaN or Infinity. Without seeing all of your code, the most likely reason for that is one of the following:
You initialize collection to an empty Object. const result = Math.ceil(undefined / undefined) will return NaN
You do correctly prevent the property from being calculated before the result comes in, but the response from the server that populates collection has a per_page of 0. The calculation mentioned above would return Infinity, and Vue would not be able to create a range from that.
There are multiple ways of dealing with this problem. The easiest way is, if you can be certain that per_page is always > 0, to put a v-if on the element around your loop. If there is no convenient element, you can use the <template> element to put around it.
Otherwise you can check in your computed property if de data you are going to calculate with, is actually correct, and otherwise return a default number.
numberOfPages() {
if (
!this.collection ||
Number.isNaN(parseInt(this.collection.total)) ||
Number.isNaN(parseInt(this.collection.per_page)) ||
this.collection.per_page <= 0
) {
return 0;
}
const result = Math.ceil(this.collection.total / this.collection.per_page)
return (result < 1) ? 1 : result
}

Like someone else said, carefully check your computed properties. I had two different "interesting" situations (bugs that I introduced):
(1) First I forgot to include the "return" keyword in my computed property!
So I was doing:
```
myComputedProp () {
arr.length
}
```
which should have been return arr.length ... easy to overlook :-)
(2) Second, the result of my calculation (which I used as an array length/size) was not an integer but a real (broken number). Solution was of course to add Math.round() or Math.trunc() ... :-)

Related

How can I save part of a string in an alias using Cypress?

I'm trying to save just a number from a string I get from a paragraph but when I try to asign an alias to it and then check the value it returns undefined. I've tried a few solutions I found but none of those seem to work for me. These are two ways I tried (I tried another one similar to the second one but using split, had same result). The console.log inside of the 'then' doesn't show in the console, and when I try the alias after the code is when I get undefined.
cy.get('p')
.eq(1)
.should('have.text', '/[0-9]+/g')
.as('solNumber')
cy.get('p')
.eq(1)
.invoke('text')
.then((text)=>{
var fullText = text;
var pattern = /[0-9]+/g;
var number = fullText.match(pattern);
console.log(number);
})
.as('solNumber')
Please convert with + operator and return the numeric value if you want numeric type to be stored.
cy.get('p').eq(1)
.invoke('text')
.then(fullText => {
const number = fullText.match(/[0-9]+/);
return +number // text to numeric
})
.as('solNumber')
cy.get('#solNumber')
.should('eq', 42) // numeric type
});
Running your 2nd code on this,
<p>21</p>
<p>42</p>
gives the correct outcome
cy.get('p')
.eq(1)
.invoke('text')
.then((text)=>{
var fullText = text;
var pattern = /[0-9]+/g;
var number = fullText.match(pattern);
console.log(number); // logs 42
})
.as('solNumber')
cy.get('#solNumber')
.should('eq', '42') // passes
So, you need to inspect the DOM, it looks like it's not what you expect.
The first attempt you were passing a jquery element to the .should() and although some chainers change the subject yours did not so it saved the jquery element as solNumber.
The second attempt invokes the .text() which was passed to the .then() it logs the number correctly. However, you did not return anything at the end of the .then() block, therefore, solNumber should hold the entire paragraph.
This should help you out to extract the specific number and save it as an alias.
cy.get('p')
.invoke('text')
.invoke('trim')
.then(paragraph => {
const matcher = /some/
expect(paragraph).to.match(matcher) // check number is there
const indexOfText = paragraph.match(matcher) // get index of match text
return paragraph.substring(indexOfText.index, indexOfText.index + indexOfText[0].length) // return substring
})
.as('savedText')
cy.get('#savedText')
.then(cy.log) // will print out the number you seek

How to create v-autocomplete which first shows items startsWith and then shows items indexOf

I would like to create a vuetify autocomplete with a custom filter that first shows the hits that start with the searchtext and then show the hits that not start with the searchtext, but have the searchtext somewhere in the middle.
I now have a custom filter like this, but this filter is not prioritizing words that start with the searchtext:
customFilter(item, queryText) {
const textOne = item.description.toLowerCase();
const textTwo = item.code.toLowerCase();
const searchText = queryText.toLowerCase();
return (
textOne.indexOf(searchText) > -1 || textTwo.indexOf(searchText) > -1
);
}
},
Codepen (Type 'ma' for example)
I believe you need to sort it manually, filter returns only true/false whether item is a match.
// https://stackoverflow.com/a/36114029/1981247
var _sortByTerm = function (data, term) {
return data.sort(function (a, b) {
// cast to lowercase
return a.toLowerCase().indexOf(term) < b.toLowerCase().indexOf(term) ? -1 : 1;
});
};
Then pass sorted array to items prop
<v-autocomplete :items="computedItems"
...
computed: {
computedItems() {
return _sortByTerm(this.states, this.search.toLowerCase())
},
},
Note this is just to get you started, and you might need to change code a bit according to the data (and filters) you are using, e.g. _sortByTerm works only on array of strings, but in the link there is a solution for sorting arrays of objects also.

Using an array data item length as part of string in a vue computed property

I have a data item
items: [],
which i am using in a computed property that returns the lengh of that array as part of a string.
itemSummary : function() {
return this.items.length === 0 ? "No Items" : "`${this.items.length}` items selected"
}
Is it possible to do this with string interpolation....?
You almost had it in your question. I think the code should be:
itemSummary() {
return this.items.length === 0 ? "No Items" : `${this.items.length} items selected`
}
With an interpolated string you put everything inside back quotes and interpolate variables or code snippets by wrapping them in ${ ... }.
See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Template_literals

Vue Object isn't returning updated value despite seeing the value updated

I'm writing tests for Vue.js and I'm trying to write the test to ensure that when some props are changed for pagination, the resulting values within the component are updated properly.
So when I console.log the component, I see the correctly updated values, but then when I try to literally grab that attribute it gives me the old and outdated value. Look at rangeList in the following screenshot to see what I mean:
Here is my code so that you see how what is generating this output.
pagComp.$refs.component.limit = 10;
pagComp.$refs.component.pages = 145;
console.log(pagComp.$refs.component);
console.log('RangList: ' + pagComp.$refs.component.rangeList.length);
Here is the code that modifies rangeList:
createListOfRanges() {
let range = [];
for(let i = 0; i < this.pages; i++) {
range.push(i);
}
this.rangeList = [];
while(range.length > 0) {
this.rangeList.push(range.splice(0, this.rangeLength));
}
this.correctLastRange();
},
Finally, there are two places this function is called: when the component is being created, and when the pages attribute changes. Here is the watcher:
watch: {
pages(val) {
this.createListOfRanges();
}
},
I see some issues with this part of your code:
while(range.length > 0) {
this.rangeList.push(range.splice(0, this.rangeLength));
}
range.splice(..) returns an array, which is getting pushed into this.rangeList
Forget about that for a minute. Look at the following example:
x = [1, 2, 3, 4]
x.splice(0, 2) // result: [1, 2]
As you can see above, splice returns an array, not an element. Now, in the same example above:
x = [1, 2, 3, 4]
y = [10, 11]
y.push(x.splice(0, 2))
Check the value of y. It will be [10, 11, [1, 2] ]. It is an array within another array. It does not look very meaningful here. You can do the above x and y experiments directly in your developer console.
In your case, your x happens to be the local range array within createListOfRanges method, and your y is this.rangeList that belongs to your Vue component.
Can you check your app logic at around that area, and see if that is really what you want to do?
For debugging Vue.js apps, you also need Vue devtools: https://github.com/vuejs/vue-devtools - it is much better than console.log()
While #Mani is right on the line of code giving you issues is your push to rangeList.
createListOfRanges() {
let range = [];
for(let i = 0; i < this.pages; i++) {
range.push(i);
}
this.rangeList = [];
while(range.length > 0) {
this.rangeList.push(range.splice(0, this.rangeLength));
}
this.correctLastRange();
},
pushing the result of the splice just makes a single element with all the elements of range in it.
try changing it to
this.rangeList.push(range.shift());
Though your function could be simplified by pushing the for(let i = 0; i < this.pages; i++) { i value directly to rangeList unless that's a simplification.
This JSFiddle shows what I'm talking about.
I appreciate the answers above, however they aren't what the issue was.
The problem was with Vue's lifecycle. I'm not 100% sure why, but when the page and limit variables are changed it takes another moment for the page watcher (shown above) to get executed and update the component. So thus it wouldn't show up in my tests. So what I did was use nextTick like so, which fixed the problem.
pagVue.limit = 10; // limit and pages change together every time automatically
pagVue.pages = 145;
Vue.nextTick(() => {
expect(pagination.rangeList.length).toBe(25);
})

Vue.js: error setting a computed property

in the following code (jsbin available here) I have two input elements, a range and a text, bound together via a computed property.
var vm = new Vue({
el: '#main-container',
data: {
sliderValue: 100,
},
computed: {
actualValue: {
get: function() {
if (this.sliderValue <= 100) {
return this.sliderValue;
} else {
return Math.round(this.sliderValue * 12.5 - 1150);
}
},
/* set won't work for val > 100*/
set: function(val) {
if (val <= 100) {
this.sliderValue = val;
} else {
this.sliderValue = Math.round((val + 1150)/12.5);
}
}
}
},
methods: {
}
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.0.3/vue.js"></script>
<div id="main-container">
<input type="range" v-model="sliderValue" min=1 max=132>
<input type="text" v-model="actualValue">
<p>Slider: {{sliderValue}}</p>
<p>Actual: {{actualValue}}</p>
</div>
The range goes from 1 to 132, and its range is mapped [1..500] in the text input, with a simple transformation (basically it's a linear mapping with two different slopes for [1..100] and [101..132]) using the actualValue computed property.
Getting actualValue works as expected: dragging the slider correctly updates the input text with appropriate values in the range [1..500].
I'm not able to find a way to set actualValue, though. I'd like to be able to type a value in the text input, and make the slider's thumb update accordingly to the inverse transformation (val + 1150)/12.5.
It works as long as the typed number is in the range [1..100], but it "explodes" for numbers >100, e.g. 101 makes the sliderValue jump at 80892 and actualValue is then re-calculated as 1010000. As far as I understand, it's a looping-feedback scenario.
I've tried also alternative approaches (watch; v-on:change in the text input; using a third variable) to no avail.
Thanks in advance for any suggestion!
It's an amazing puzzle, and challenged me for a long time!
Look at the screenshot below. Your sliderValue and actualValue are strings, not integers. When you set actualValue as 101, you are actually setting it as a string value of "101"
Now, your sliderValue = ((actualValue + 1150)/12.5)
"101" + 1150 = "1011150" (another string!, try it in the developer console)
That messes up your entire calculation. Now you know how to fix it :-)
And you need to get that Vue devtools from here: https://github.com/vuejs/vue-devtools
EDIT: Response to comment #3
Here is the modified jsBin: http://jsbin.com/mahejozeye/1/edit?html,js,output
The only difference is introduction of two console.log statements in your map2 function. This helps you identify if your non-linear mapping function is working correctly or not. If you keep your developer console open, you will see what is happening in this function.
Case 1: When you set the value radius = 25 using the text box, your sliderRadius gets set to 111.55518394648828 and your radius again gets re-calculated as 25. So it comes around in a full circle and everything is stable here.
Case 2: When you set the value radius = 55, your sliderRadius gets set to 173.03607214428857 through your non-linear map2() function, which resets radius to 51.29869180420927
Clearly there is a circular dependency issue. Your sliderRadius and radius are very much dependent on each other and therefore radius is unable to take the value between 51 and 58.
You need to evaluate why it happens, as it has a lot to do with the non-linear mapping function that you have defined. The moment radius can take stable values at 55 (through the map2 function), then your current problem will be resolved.
The simplest fix is to set your input type to number:
<input type="number" v-model="actualValue">
or you can convert your value to an integer with something like:
set: function(val) {
var intVal = parseInt(val, 10);
if (!isNaN(intVal)) {
if (intVal <= 100) {
this.sliderValue = Math.max(1, intVal);
} else {
this.sliderValue = Math.min(132, Math.round((intVal + 1150) / 12.5));
}
}
}