Iterating through an array with a fakeAPI promise function Vue.js

Question

 <template> <div class="hello"> <h1>Example 2</h1> <input @click="send" type="button" value="Send" /> <div class="out" v-if="successIds.length">{{ successIds }}</div> </div> </template> <script> /* @return resolve: { id: 1, success: true } or reject: { success: false } */ const fakeApiRequest = (id) => { return new Promise((resolve, reject) => { setTimeout(() => { const success = id % 2; success? resolve({ id, success }): reject({ success }); }, 2000); }); }; export default { data() { return { // Fetch ids ids: [1, 2, 3, 4, 5, 6], // Complete ids successIds: [], }; }, methods: { // iterating through the ids array newValues(id) { this.ids.forEach((el) => el.this.fakeApiRequest(id)); }, // filling the successIds array send(id) { this.$set(this, "successIds", this.newValues(id)); }, }, }; </script>

How can I fill and display the successId array in the template with the iterated elements of the existing array using Promise function within a $set Vue method? I seem to fail trying to reach the fakeApiRequest in the newValues function.

Answer 1

I'm not sure why you think you need to use the $set method. There are clear documented uses for it , and setting/replacing an array is not one. Besides that though, to be frank, there are a lot of issues with your code, and it's not very clear what you're trying to do, but I did my best to correct all the issues and left comments describing my changes.

sandbox example

<template>
  <div class="hello">
    <h1>Example 2</h1>
    <input type="button" value="Send" @click="send" />
    <div v-if="successIds.length" class="out">{{ successIds }}</div>
  </div>
</template>

<script>
export default {
  data() {
    return {
      // Fetch ids
      ids: [1, 2, 3, 4, 5, 6],
      // Complete ids
      successIds: []
    };
  },
  methods: {
    // note 1: method loops through all ids so not sure what the 'id' param is for
    // note 2: calling other async methods requires we use 'async' and 'await' keywords
    async newValues(id) {
      // note 3: the code in this method before was non-sensical to me, e.g. "el.this.fakeApiRequest" isn't valid syntax
      // and the forEach loop didn't do anything with the actual result returned by fakeApiRequest.
      // note 4: forEach actually isn't designed for async code. Must use normal for loop
      const results = [];
      for (let i = 0; i < this.ids.length; i++) {
        let res = null;
        try {
          res = await this.fakeApiRequest(this.ids[i]);
        } catch (rejectVal) {
          res = rejectVal;
        }
        console.log('res', res);
        results.push(res);
      }
      return results;
    },
    // note 5: not sure why id is a param as this method isn't called with any specific id
    async send(id) {
      // note 6: the use of $set before was unnecessary
      this.successIds = await this.newValues();
    },
    /*
    @return
      resolve: { id: 1, success: true }
      or
      reject: { success: false }
    */
    // note 7: moved this here so it can be called by other methods. decreased timeout time for sanity's sake
    fakeApiRequest(id) {
      return new Promise((resolve, reject) => {
        setTimeout(() => {
          const success = id % 2;
          success ? resolve({ id, success }) : reject({ success });
        }, 100);
      });
    }
  }
};
</script>