Multiple mdbSelect With Identical Options

Topic: Multiple mdbSelect With Identical Options

atticuss free asked 4 years ago

I'm building a recipe application to learn a few different technologies. When creating a new recipe, the user can add an arbitrary number of ingredients. I solved this with the following snippet of relevant template code:

<mdb-tbl>
    <mdb-row
    v-for="idx in numIngredients"
    :index="idx"
    :key="idx"
    class="justify-content-start"
    >

    <mdb-col col="7">
        <mdb-select
        v-model:"ingredients"
        placeholder="Select an ingredient"
        label=""
        search
        >
        </mdb-select>
    </mdb-col>

    </mdb-row>
</mdb-tbl>

And within the script code, I load all the ingredients via axios:

created() {
    IngredientAPI.getIngredients().then(data => {
        this.ingredients = data.ingredients.map(ing => {
            return { text: ing.name, value: ing.uid };
        });
    });
}

This works great for a single mdbSelect, but I (obviously) need to add multiple ingredients. By using v-model, the two binding makes it so that any update to one mdbSelect updates all mdbSelect components. Expected behavior. However, I'm struggling with how to fix this behavior. I've tried a several solutions to no avail. For example:

<mdb-select
:options="ingredients"
:selected="getSelected(idx)"
@change="updateSelected($event, idx)"
placeholder="Select an ingredient"
label=""
search
/>

getSelected(idx) {
  console.log(`get selected: ${idx}`);
  return this.selectedIngredients[idx];
},
updateSelected(val, idx) {
  console.log(`update selected: ${val} - ${idx}`);
  this.selectedIngredients[idx] = { text: val, value: val };
},

Or:

<mdb-select
v-model="ingredients"
:selected="selectedIngredients[idx]"
placeholder="Select an ingredient"
label=""
search
/>

The obvious solution is to create a separate array for each mdbSelect; however, this feels incredibly hacky and would almost certainly cause performance issues once I have hundreds of ingredient choices. Is there a way to provide each mdbSelect with a list of options whilst maintaining a list of what each mdbSelect has selected independently? Thanks in advance.

Mikołaj Smoleński staff commented 4 years ago

In such case it's necessary to create a new list for each select. Best regards

atticuss free commented 4 years ago

Well that's pretty unfortunate. But I anticipated this and decided to not preload any items and instead rely on the @search and adisableFilter. However, I'm having trouble getting my array to be reactive to data changes. For example:

<mdb-select
disableFilter
@search="handleIngredientSearch($event, idx)"
v-model="ingredients[0]"
placeholder="Select an ingredient"
label=""
search

...

data() {
    return {
    newValues: [],
    render: false,
    ingredients: [[]],
    numIngredients: 1,
    tags: [],
    recipes: []
    };
},
methods: {
handleIngredientSearch(text, idx) {
    console.log(`text: ${text}`);
    console.log(`idx: ${idx}`);
    if (text.length >= 3) {
    IngredientAPI.searchIngredients(text).then(data => {
        this.ingredients[0] = data.ingredients.map(ing => {
        return { text: ing.name, value: ing.uid };
        });
        console.log(this.ingredients[0]);
    });
    }
},
}

this.ingredients[0] updates just fine, but the items are not added to the list presented by mdbSelect. I'm guessing this has to do with an implementation detail of how v-model handles two-way binding? It's worth noting this works fine if I just bind to ingredients, and that I'm only explicitly indexing at 0 as a POC.

<p>Well that's pretty unfortunate. But I anticipated this and decided to not preload any items and instead rely on the <code>@search</code> and a<code>disableFilter</code>. However, I'm having trouble getting my array to be reactive to data changes. For example:</p>

<pre class="prettyprint"><code><mdb-select
disableFilter
@search="handleIngredientSearch($event, idx)"
v-model="ingredients[0]"
placeholder="Select an ingredient"
label=""
search

...

data() {
    return {
    newValues: [],
    render: false,
    ingredients: [[]],
    numIngredients: 1,
    tags: [],
    recipes: []
    };
},
methods: {
handleIngredientSearch(text, idx) {
    console.log(`text: ${text}`);
    console.log(`idx: ${idx}`);
    if (text.length >= 3) {
    IngredientAPI.searchIngredients(text).then(data => {
        this.ingredients[0] = data.ingredients.map(ing => {
        return { text: ing.name, value: ing.uid };
        });
        console.log(this.ingredients[0]);
    });
    }
},
}
</code></pre>

<p><code>this.ingredients[0]</code> updates just fine, but the items are not added to the list presented by mdbSelect. I'm guessing this has to do with an implementation detail of how <code>v-model</code> handles two-way binding? It's worth noting this works fine if I just bind to <code>ingredients</code>, and that I'm only explicitly indexing at 0 as a POC.</p>

Please insert min. 15 characters.

atticuss free commented 4 years ago

Ah sorry -- still new to Vue and just found the reactivity caveats within the docs. If anyone stumbles across this later, the solution is to replace:

this.ingredients[0] = options;

with:

this.$set(this.ingredients, 0, options);

This will trigger state updates and update component data accordingly. More info for noobs like me:

https://vuejs.org/v2/guide/reactivity.html#For-Arrays

That said: I'd heavily recommend you consider expanding the mdbSelect component to be able to easily delineate between a list of options and the selected value. I can't imagine this use-case is very novel, and it hurts my inner engineer to see data pointlessly copied like in the originally proposed solution.

Please insert min. 15 characters.

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Status

Resolved

Specification of the issue

ForumUser: Free
Premium support: No
Technology: MDB Vue
MDB Version: 6.7.2
Device: PC
Browser: Firefox
OS: OSX
Provided sample code: Yes
Provided link: No

atticuss

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