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Create with JavaScript "Excel → JSON conversion application"

leen profile image leen ・2 min read

Author:@yama_cqw
Source:Qiita

Introduction

For development, use "script editor" which is included as standard in Mac (OS X Yosemite or later).

It's a very simple editor.

Launch the script editor.
Select "JavaScript" in the language menu in the upper left. (You can choose AppleScript or JavaScript)
Write the code.
File -> Export (file format: application).
You can create an application by this alone. Easy.

Application

The code of the created application is here.
When you drag and drop an Excel file, the JSON file is exported.
(Note: Microsoft Excel must be installed for execution.)

function analyzeExcel(path) {
  var app, worksheets;
  app = Application('Microsoft Excel');
  app.includeStandardAdditions = true;
  app.activate();
  app.open(path);
  worksheets = app.worksheets;

  // Create JSON for each worksheet.
  for (var i = 0; i < worksheets.length; i++) {
    makeJSON(worksheets[i]);
  }

  function makeJSON(ws) {
    var data = {};
    var title = [];
    var first_row = ws.rows[0];
    var worksheet_name = ws.name();

    // Acquire line 1 as heading.
    for (var col_i = 0; ; col_i++) {
       var check = first_row.columns[col_i].value();
       if (!check) {
          break;
       }
       title.push(check);
    }

    // Acquire as data from the second line
    for (var row_i = 1; ; row_i++) {
       var row = ws.rows[row_i];
       var row_data = {};
       // Determine the presence or absence of data in the first column.
       var id = row.columns[0].value();
       if (!id) {
          break;
       } else {
          data[id] = {};
       }
       // Combine data row by row.
       // If it has the same heading, put it in an array.
       for (var i = 1; i < title.length; i++) {
          if (row_data[title[i]]) {
             // 配列化
             if (!Array.isArray(row_data[title[i]])) {
                row_data[title[i]] = [row_data[title[i]]];
             }
             // Add
             if (row.columns[i].value()) {
                row_data[title[i]].push(row.columns[i].value());
             }
          } else {
             row_data[title[i]] = row.columns[i].value();
          }
       }
       data[id] = row_data;
    }

    // Export settings
    var filePath = app.chooseFileName({
       defaultName: worksheet_name + '.json',
       defaultLocation: app.pathTo('desktop')
    });

    // Write JSON data (convert character code to UTF-8)
    ObjC.import('Cocoa');
    var text = JSON.stringify(data, null, '  ');
    string = $.NSString.stringWithString(text);
    string.writeToFileAtomicallyEncodingError(
      filePath.toString(),
      true,
      $.NSUTF8StringEncoding,
      $()
    );
  }
}

// Processing when dragging and dropping a file to an application.
var SystemEvents = Application("System Events");
var fileTypesToProcess = ["ELSX"];
var extensionsToProcess = ["xlsx"];
var typeIdentifiersToProcess = [];
function openDocuments(droppedItems) {
  for (var item of droppedItems) {
    var alias = SystemEvents.aliases.byName(item.toString());
    var extension = alias.nameExtension();
    var fileType = alias.fileType();
    var typeIdentifier = alias.typeIdentifier();
    if (
       fileTypesToProcess.includes(fileType) 
       || extensionsToProcess.includes(extension)
       || typeIdentifiersToProcess.includes(typeIdentifier)
    ) {
      var path = Path(item.toString().slice(1));
      analyzeExcel(path);
    }
  }
}

// Describe how to use when double-clicking the application icon
function run() {
  var sys = Application("System Events");
  sys.includeStandardAdditions = true;
  sys.displayDialog("Please drag and drop the Excel file (xlsx). Convert to JSON file.");
}

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Here is the conversion rule.

  • Create a JSON file for each Excel worksheet.
  • Heading the first line, treat the second and subsequent lines as values.
  • Use the value of the first column as the key and group the data for each row.
  • If the headings are the same, make it an array.
  • Convert to UTF-8 (garbled characters if not converted).

For example, if you drag and drop such an Excel file...

Such JSON will be exported!

{
  "a": {
    "name": "John",
    "num": [
      11,
      12,
      13
    ]
  },
  "b": {
    "name": "Paul",
    "num": [
      21,
      22
    ]
  },
  "c": {
    "name": "George",
    "num": [
      31
    ]
  },
  "d": {
    "name": "Ringo",
    "num": ""
  }
}
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Discussion (2)

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Editor guide
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bossajie profile image
Boss A

how can I use it with React JS?

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pankajkumar profile image
Pankaj Kumar

Did the same task with Node.js very easily by following link: jsonworld.com/demo/excel-to-json-i...