Javascript - Manage v-model value in a v-select created in a v-for

BaptisteRousseau
October 31, 2023
221 views
0 votes
2 Answers

I have a table of members created by a v-for and some users can manage other members based on their role. I implemanted some check to prevent some role to intervene but the complete list of check is done in the backend.

Managing is done with a v-select and I want to be able to revert the v-select choice is the user was not authorized to perform this action.

This was what I made at first:

<template>
  <tr v-for="member in members" :key="member.username">
    <td>{{ member.username }}</td>
    <td>
      <v-select
        density="compact"
        hide-details="true"
        v-model="member.role"
        :items="dialog_roles"
        :item-props="itemProps"
        @update:modelValue="changeRole(member)"
      ></v-select>
    </td>
</template>

<script>
  export default {
    data: () => ({
      members: [
        {
          username: 'John',
          role: {
            role: 'owner',
            description: 'full access to the project, can delete it and can manage members'
          },
        },
        {
          username: 'Jane',
          role: {
            role: 'manager',
            description: 'full access to the project, and can manage members'
          },
        },
        {
          username: 'Joe',
          role: {
            role: 'collaborator',
            description: 'can view the project but not modify any content'
          },
        },
      ],
      dialog_roles: [
              {
                "role": "owner",
                "description": "full access to the project, can delete it and can manage members"
              },
              {
                "role": "manager",
                "description": "full access to the project, and can manage members"
              },
              {
                "role": "contributor",
                "description": "full access to the project, but cannot delete it"
              },
              {
                "role": "collaborator",
                "description": "can view the project but not modify any content"
              }
            ]
    }),
    methods: {
        itemProps(item) {
          return {
            title: item.role,
            subtitle: item.description,
          };
        },
        changeRole(member) {
          //make API call to change the role
          //if it was unauthorized, change back the role in the v-select
        },
    }
  }
</script>

In order to be able to get the old and new value when updating the v-select I moved from v-model="member.role" to a simple :value=member.role.role which then give @update:modelValue="changeRole(member, $event)" where member store the initial value and $event the updated one.

Now that I have that, how do I apply this change if the API call is effective, and how do I revert it if it’s not ?

Answers

To apply the change if the API call is effective and revert it if it’s not, you can update the changeRole method in your Vue component.

<template>
  <tr v-for="member in members" :key="member.username">
    <td>{{ member.username }}</td>
    <td>
      <v-select
        density="compact"
        hide-details="true"
        :value="member.role.role"  <!-- Use :value to bind the role.role value -->
        :items="dialog_roles"
        :item-props="itemProps"
        @update:modelValue="changeRole(member, $event)"
      ></v-select>
    </td>
  </tr>
</template>

<script>
export default {
  data: () => ({
    // Your data here
  }),
  methods: {
    // ...

    async changeRole(member, newRole) {
      const oldRole = member.role.role; // Store the old role
      member.role.role = newRole; // Update the local data immediately

      // Make an API call to change the role
      try {
        // Example: If your API call returns an error, you can handle it here
        // if (response.error) {
        //   member.role.role = oldRole; // Revert the role
        //   console.error('API call failed. Reverted role.');
        // }
      } catch (error) {
        // Handle API call errors here
        console.error('API call failed. Reverted role.');
        member.role.role = oldRole; // Revert the role
      }
    },
  },
};
</script>

first you also need to pass the index in your for loop. it’s important to be able to update the member value later.

 <tr v-for="(member, index) in members" :key="member.username"

you then need to pass the index, to your change role function

changeRole(member, index)

now within this function you have to cache your values from the latest change.

// globally defined
let cachedValues = {
    member: null,
    index: null
};

changeRole(member, index) {
    cachedValues.member = member;
    cachedValues.index = index

    try {
      // make your api call
      // if unauthorized, throw error
    } catch {
      // change back values by taking them from cachedValues
    }
}

If you already want to cache the values from before the change, you can save a whole copy of your members array on state, which is only changed after the submission was successful.

Example implementation:

<script>
  export default {
    data: () => ({
      members: [
        {
          username: 'John',
          role: {
            role: 'owner',
            description: 'full access to the project, can delete it and can manage members'
          },
        },
        {
          username: 'Jane',$
          role: {
            role: 'manager',
            description: 'full access to the project, and can manage members'
          },
        },
        {
          username: 'Joe',
          role: {
            role: 'collaborator',
            description: 'can view the project but not modify any content'
          },
        },
      ],
      membersCache: [
        {
          username: 'John',
          role: {
            role: 'owner',
            description: 'full access to the project, can delete it and can manage members'
          },
        },
        {
          username: 'Jane',$
          role: {
            role: 'manager',
            description: 'full access to the project, and can manage members'
          },
        },
        {
          username: 'Joe',
          role: {
            role: 'collaborator',
            description: 'can view the project but not modify any content'
          },
        },
      ],
    }),
    methods: {
        itemProps(item) {
          return {
            title: item.role,
            subtitle: item.description,
          };
        },
        changeRole(member, index) {
            try {
              // make your api call
              // if unauthorized, throw error
              // if authorized also adjust cached array and use $set to force reactivity
              this.$set(this.membersCache, index, member)
            } catch {
              // change back values by taking them from cachedValues
              const cachedMember = this.membersCache[index];
              this.$set(this.members, index, cachedMember)
            }
        }
    }
  }
</script>

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Javascript – Manage v-model value in a v-select created in a v-for

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