javascript - How get data from JSON file by readfile in Vue? - Stack Overflow

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I can't read of JSON file content, I tried to access the contents of the file by ReadFile but I did not success, I get string empty for content and url is undefined,

My Code:

<template>
 <div class="large-12 medium-12 small-12 cell">
   <input type="file" accept="application/JSON" @change="onFileChange" class="inputFile" />
 </div>
</template>

<script>
import Vue from "vue";

export default {
 data() {
   return {};
 },
 methods: {
   onFileChange(e) {
     let files = e.target.files || e.dataTransfer.files;
     if (!files.length) return;
     this.readFile(files[0]);
   },
   readFile(file) {
     let reader = new FileReader();
     reader.onload = e => {
       this.readContentFile = e.target.result;
       console.log(this.readFile);
     };
     let url = reader.readAsDataURL(file);
     let content =reader.result;
     console.log(url);
     console.log(content);
   }
 }
};
</script>

I can't read of JSON file content, I tried to access the contents of the file by ReadFile but I did not success, I get string empty for content and url is undefined,

My Code:

<template>
 <div class="large-12 medium-12 small-12 cell">
   <input type="file" accept="application/JSON" @change="onFileChange" class="inputFile" />
 </div>
</template>

<script>
import Vue from "vue";

export default {
 data() {
   return {};
 },
 methods: {
   onFileChange(e) {
     let files = e.target.files || e.dataTransfer.files;
     if (!files.length) return;
     this.readFile(files[0]);
   },
   readFile(file) {
     let reader = new FileReader();
     reader.onload = e => {
       this.readContentFile = e.target.result;
       console.log(this.readFile);
     };
     let url = reader.readAsDataURL(file);
     let content =reader.result;
     console.log(url);
     console.log(content);
   }
 }
};
</script>

• javascript
• json
• vue.js
• readfile

Share Improve this question Follow asked Mar 4, 2020 at 14:56 Nir AmirNir Amir 13033 silver badges1414 bronze badges

Add a ment  | 

1 Answer 1

Sorted by: Reset to default 5

You almost had it. reader.onload is like a callback for when file has finished loading, so your console.logs near the bottom would happen before the file has loaded. Hopefully you should find this snippet helpful.

new Vue ({
 el: "#app",
 methods: {
   onFileChange(e) {
     let files = e.target.files || e.dataTransfer.files;
     if (!files.length) return;
     this.readFile(files[0]);
   },
   readFile(file) {
     let reader = new FileReader();
     reader.onload = e => {
       console.log(e.target.result);
       let json = JSON.parse(e.target.result);
     };
     reader.readAsText(file);
   }
 }
});

<script src="https://cdnjs.cloudflare./ajax/libs/vue/2.5.17/vue.js"></script>
<div class="large-12 medium-12 small-12 cell" id="app">
   <input type="file" accept="application/json" @change="onFileChange">
</div>

I can't read of JSON file content, I tried to access the contents of the file by ReadFile but I did not success, I get string empty for content and url is undefined,

My Code:

<template>
 <div class="large-12 medium-12 small-12 cell">
   <input type="file" accept="application/JSON" @change="onFileChange" class="inputFile" />
 </div>
</template>

<script>
import Vue from "vue";

export default {
 data() {
   return {};
 },
 methods: {
   onFileChange(e) {
     let files = e.target.files || e.dataTransfer.files;
     if (!files.length) return;
     this.readFile(files[0]);
   },
   readFile(file) {
     let reader = new FileReader();
     reader.onload = e => {
       this.readContentFile = e.target.result;
       console.log(this.readFile);
     };
     let url = reader.readAsDataURL(file);
     let content =reader.result;
     console.log(url);
     console.log(content);
   }
 }
};
</script>

I can't read of JSON file content, I tried to access the contents of the file by ReadFile but I did not success, I get string empty for content and url is undefined,

My Code:

<template>
 <div class="large-12 medium-12 small-12 cell">
   <input type="file" accept="application/JSON" @change="onFileChange" class="inputFile" />
 </div>
</template>

<script>
import Vue from "vue";

export default {
 data() {
   return {};
 },
 methods: {
   onFileChange(e) {
     let files = e.target.files || e.dataTransfer.files;
     if (!files.length) return;
     this.readFile(files[0]);
   },
   readFile(file) {
     let reader = new FileReader();
     reader.onload = e => {
       this.readContentFile = e.target.result;
       console.log(this.readFile);
     };
     let url = reader.readAsDataURL(file);
     let content =reader.result;
     console.log(url);
     console.log(content);
   }
 }
};
</script>

• javascript
• json
• vue.js
• readfile

Share Improve this question Follow asked Mar 4, 2020 at 14:56 Nir AmirNir Amir 13033 silver badges1414 bronze badges

Add a ment  | 

1 Answer 1

Sorted by: Reset to default 5

You almost had it. reader.onload is like a callback for when file has finished loading, so your console.logs near the bottom would happen before the file has loaded. Hopefully you should find this snippet helpful.

new Vue ({
 el: "#app",
 methods: {
   onFileChange(e) {
     let files = e.target.files || e.dataTransfer.files;
     if (!files.length) return;
     this.readFile(files[0]);
   },
   readFile(file) {
     let reader = new FileReader();
     reader.onload = e => {
       console.log(e.target.result);
       let json = JSON.parse(e.target.result);
     };
     reader.readAsText(file);
   }
 }
});

<script src="https://cdnjs.cloudflare./ajax/libs/vue/2.5.17/vue.js"></script>
<div class="large-12 medium-12 small-12 cell" id="app">
   <input type="file" accept="application/json" @change="onFileChange">
</div>

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