A Practical Front end reading excel table Getting Started Guide With Vue and XLSX

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In this tutorial, we are going to implement Front end reading excel tables and get the content of the file ,Without back-end interface.

• Use it to learn important XLSX features.
• My other articles address expansion requirements：
• Automatic cell merging after reading and parsing excel tables
• Set cell color automatically after read and analyze the excel tables , then compare and analyze according to the data.
• Perform data analysis after Reading the analysis excel tables（dialysis） Generate the echarts diagram that can meet the user-defined requirements.
• Download excel tables

Introduction

There are many Background Management Systems in my company. It's very common to upload, parse and download excel tables. I've written similar posts before, but I only put the code and never write comments and steps. Haha, I don't say much. This article is a complete record:

Prerequisites

I usually use the following techniques：

Ant Design + Angular

Element UI + Vue

Ant Design + Vue

For convenience ,today we use Element UI + Vue

Start directly based on vue-element-admin

Step 1：Preparation

1. Click to download vue-element-admin

2. Download and unzip

3. Install dependency and run

Your project should resemble the following:

4. Run successfully

You will see a Login Form System web interface.

Step2：Import and parse tables

### 1. Enter the following path；

src\views\dashboard\index.vue

### 2. Delete useless code, prepare to start；

<template>
  <div class="dashboard-container">
  </div>
</template>

<script>
export default {
  name: 'Dashboard'
}
</script>

<style lang="scss" scoped>

</style>

### 3. Add import button

<template>
  <div class="dashboard-container">
    <!-- Import button -->
    <div class="button_group">
      <a
        href="javascript:;"
        class="button_s my_file el-button button_s el-button--primary el-button--small"
      >
        <input type="file" class="my_input" @change="importExcel" id="upload" />Import
      </a>
    </div>
    <!-- Import button -->
  </div>
</template>

<script>
export default {
  name: 'Dashboard',
  methods: {
    /**
     * Import table
     */
     importExcel(e) {
    }
  }
}
</script>

<style lang="scss" scoped>
// Button style
.button_group {
  .button_s {
    width: 78px;
    margin: 5px 10px 5px 5px;
  }
  .button_m {
    width: 100px;
    margin: 5px 10px 5px 5px;
  }
  .my_file {
    position: relative;
    .my_input {
      position: absolute;
      opacity: 0;
      width: 78px;
      height: 30px;
      top: 0;
      left: 0;
    }
  }
}
// Button style
</style>

### 4. Save and refresh；

### 5. Download xlsx And Import xlsx；

### 6. Write Import Table function code, Save and Refresh；

<script>
import xlsx from "xlsx";
export default {
  name: 'Dashboard',
  methods: {
    /**
     * Import table
     */
     importExcel(e) {
      const files = e.target.files;
      console.log(files);
      if (!files.length) {
        return ;
      } else if (!/\.(xls|xlsx)$/.test(files[0].name.toLowerCase())) {
        return alert("The upload format is incorrect. Please upload xls or xlsx format");
      }
      const fileReader = new FileReader();
      fileReader.onload = ev => {
        try {
          const data = ev.target.result;
          const XLSX = xlsx;
          const workbook = XLSX.read(data, {
            type: "binary"
          });
          const wsname = workbook.SheetNames[0]; // Take the first sheet，wb.SheetNames[0] :Take the name of the first sheet in the sheets
          const ws = XLSX.utils.sheet_to_json(workbook.Sheets[wsname]); // Generate JSON table content，wb.Sheets[Sheet名]    Get the data of the first sheet
          const excellist = [];  // Clear received data
          // Edit data
          for (var i = 0; i < ws.length; i++) {
            excellist.push(ws[i]);
          }
          console.log("Read results", excellist); // At this point, you get an array containing objects that need to be processed
        } catch (e) {
          return alert("Read failure!");;
        }
      };
      fileReader.readAsBinaryString(files[0]);
      var input = document.getElementById("upload");
      input.value = "";
    }
  }
}
</script>

### 7. Write the following table to test the function ；

### 8. Sometimes, the table title is Chinese. If we want to get the English attribute name in Object After the table is parsed successfully , Add The Following Code and test again;

<script>
import xlsx from "xlsx";
export default {
  name: 'Dashboard',
  methods: {
    getHeader(sheet) {
      const XLSX = xlsx;
      const headers = [];
      const range = XLSX.utils.decode_range(sheet["!ref"]); // worksheet['!ref'] Is the valid range of the worksheet
      let C;
      /* Get cell value start in the first row */
      const R = range.s.r; //Line / / column C
      let i = 0;
      for (C = range.s.c; C <= range.e.c; ++C) {
        var cell =
          sheet[
            XLSX.utils.encode_cell({ c: C, r: R })
          ]; /* Get the cell value based on the address  find the cell in the first row */
        var hdr = "UNKNOWN" + C; // replace with your desired default
        // XLSX.utils.format_cell Generate cell text value
        if (cell && cell.t) hdr = XLSX.utils.format_cell(cell);
        if(hdr.indexOf('UNKNOWN') > -1){
          if(!i) {
            hdr = '__EMPTY';
          }else {
            hdr = '__EMPTY_' + i;
          }
          i++;
        }
        headers.push(hdr);
      }
      return headers;
    },
    /**
     * Import table
     */
     importExcel(e) {
      const files = e.target.files;
      console.log(files);
      if (!files.length) {
        return ;
      } else if (!/\.(xls|xlsx)$/.test(files[0].name.toLowerCase())) {
        return alert("The upload format is incorrect. Please upload xls or xlsx format");
      }
      const fileReader = new FileReader();
      fileReader.onload = ev => {
        try {
          const data = ev.target.result;
          const XLSX = xlsx;
          const workbook = XLSX.read(data, {
            type: "binary"
          });
          const wsname = workbook.SheetNames[0]; // Take the first sheet，wb.SheetNames[0] :Take the name of the first sheet in the sheets
          const ws = XLSX.utils.sheet_to_json(workbook.Sheets[wsname]); // Generate JSON table content，wb.Sheets[Sheet名]    Get the data of the first sheet
          const excellist = []; // Clear received data
          // Edit data
          for (var i = 0; i < ws.length; i++) {
            excellist.push(ws[i]);
          }
          console.log("Read results", excellist); // At this point, you get an array containing objects that need to be processed
          // Get header2-1
          const a = workbook.Sheets[workbook.SheetNames[0]];
          const headers = this.getHeader(a);
          console.log('headers', headers);
          // Get header2-2
        } catch (e) {
          return alert("Read failure!");;
        }
      };
      fileReader.readAsBinaryString(files[0]);
      var input = document.getElementById("upload");
      input.value = "";
    }
  }
}
</script>

We change the form to irregular state, save and open the interface for testing

Step 3: implement table rendering

### 1. Add table component to the interface 。

<!-- Table components -->
    <div class="myTable">
      <el-table
        max-height="600"
        :data="dataArr"
        v-loading="tableLoading"
        :span-method="objectSpanMethod"
        border
        style="width: 100%"
      >
        <el-table-column
          :prop="item.prop"
          :label="item.label"
          :width="item.width"
          v-for="(item, i) in tableColumn"
          :key="i"
        ></el-table-column>
      </el-table>
    </div>
    <!-- Table components -->

data() {
    return {
      dataArr: [], // Table content data array
      // countArr: {}, // Analyze the table data and header to get a cross reference array for user-defined consolidation. For the time being, this article only writes the basis, and does not introduce the automatic consolidation of cells~~My other articles have custom merge implementation methods~
      tableColumn: [], // Table header configuration array
      tableLoading: false // Whether the table is loading
    };
  },

### 2. Add Table Rendering Method

Note: part of the code in the table rendering method is used to map attribute names in Chinese and English. This is a function I added. Sometimes I don't need to use it. You can modify the code according to your requirements;

setTable(headers, excellist) {
      const tableTitleData = []; // Store table header data
      const tableMapTitle = {}; // Set table content for Chinese and English
      headers.forEach((_, i) => {
        tableMapTitle[_] = "prop" + i;
        tableTitleData.push({
          prop: "prop" + i,
          label: _,
          width: 100
        });
      });
      console.log("tableTitleData", tableTitleData);
      // Mapping table content attribute name is English
      const newTableData = [];
      excellist.forEach(_ => {
        const newObj = {};
        Object.keys(_).forEach(key => {
          newObj[tableMapTitle[key]] = _[key];
        });
        newTableData.push(newObj);
      });
      console.log('newTableData',newTableData);
      this.tableColumn = tableTitleData;
      this.dataArr = newTableData;
    },

3. Call Table Rendering Method

        // Add the following code to the importexcel (E) method
          // Render table1-1
          this.setTable(headers, excellist);
          // Render table1-2

4. Carry on function test

Conclusion

This code supports irregular data and can also be rendered to the interface if there is no header~~
Welcome to point out the error of my code~

If there is a better way to write, welcome to come up with it and make progress together~~