actual-csv-to-json-parser

actual-csv-to-json-parser

This tool converts from CSV to Object arrays, or JSON. It can do TSV too. Here's a super basic example.

1. Install

   npm i actual-csv-to-json-parser

2. Call Function

   import { csvTextToObjectArray } from "actual-csv-to-json-parser";
   
   const numbers = csvTextToObjectArray(`
     name, num, even
     ten, 10, TRUE
     fifteen, 15, FALSE
   `);
   
   console.log(numbers[0]) // --> { name: "ten", num: 10, even: true }
   console.log(numbers[1]) // --> { name: "fifteen", num: 15, even: false }
   

   --alternatively--

   import { csvFileToObjectArraySync } from "actual-csv-to-json-parser";
   import * as pathTool from "path";
   
   const csvLoadPath = pathTool.join(__dirname, "/path/to/file.csv");
   const items = csvFileToObjectArraySync(csvLoadPath);
   items.forEach((item) => console.log(item));
   

   --or as an extreme example--

   import { CsvParser } from "actual-csv-to-json-parser";
   import * as pathTool from "path";
   
   const csvLoadPath = pathTool.join(__dirname, "/path/to/file.csv");
   const jsonSavePath = pathTool.join(__dirname, "/path/to/output.json");
   
   // all the bells and whistles
   const parser = new CsvParser({
     delimiter: /,/,     // default
     jsonTabSize: 2,     // default
     trimRawText: true,  // default
     convertPrimitives: ["boolean", "number", "array", "object"],  // default
   });
   
   // load a csv file, modify it, save it as json
   parser.convertFileToJsonFileSync<{name: string, age: number}>(csvLoadPath, jsonSavePath, (items) => {
     items.forEach((item) => item.age += 1);
     return items;
   })
   

See "Overview of Functions" for more

---

Features

• Simple one liner functions
• Turns CSV into 2d String Array, JSON, or Object Array
• Handles quotes and commas just fine
• Can parse primitives (number, string, array, boolean, object)
• Can take raw CSV text
• Can do synchronous and asynchronous file loading
• Can set special delimiters (ie tabs for TSV)
• Typescript
• 150 lines
• That's it.

If you want a typescript interface of your json object, check out this tool: http://json2ts.com/

---

Overview of Functions

More later, but this is the basics of what exists

Default quick functions

• Creating Object Arrays
  • csvTextToObjectArray(rawCsvText)
  • async csvFileToObjectArray(csvFilePath)
  • csvFileToObjectArraySync(csvFilePath)
• Creating 2D String Arrays
  • csvTextTo2dArray(rawCsvText)
  • async csvFileTo2dArray(csvFilePath)
  • csvFileTo2dArraySync(csvFilePath)
• Creating JSON strings/files
  • csvTextToJsonText(rawCsvText)
  • async csvFileToJsonFile(csvFilePath, jsonSavePath)
  • csvFileToJsonFileSync(csvFilePath, jsonSavePath)

Custom specialty stuff. Same as above but with customized csv parser args

• ICsvParserArgs { delimiter, jsonTabSize }
• new CsvParser(customizationArgs)
  • this.rawTextTo2dArray(rawCsvText)
  • this.fileTo2dArray(csvFilePath)
  • this.fileTo2dArraySync(csvFilePath)
  • this.rawTextToObjectArray(rawCsvText)
  • this.fileToObjectArray(csvFilePath)
  • this.fileToObjectArraySync(csvFilePath)
  • this.rawTextToJsonText(rawCsvText)
  • this.convertFileToJsonFile(csvFilePath, jsonSavePath)
  • this.convertFileToJsonFileSync(csvFilePath, jsonSavePath)

---

What's a CSV or JSON or Object Array?

• This is a CSV (Comma Separated Values):

  name, age, eyesight
  bob, 21, 20/20
  julie, 27, 21/19
  mark, 42, 17/17
  

• This is an 2D String Array

  const peeps = [
    [ "name", "age", "eyesight" ],
    [ "bob", "21", "20/20" ],
    [ "julie", "27", "21/19" ],
    [ "mark", "42", "17/17" ],
  ]
  

• This is an object array (probably what you want)

  const peeps = [
    { name: "bob", age: "21", eyesight: "20/20"},
    { name: "julie", age: "27", eyesight: "21/19"},
    { name: "mark", age: "42", eyesight: "17/17"},
  ]
  

• This is json (JSON is a string)

  const json = `[
    {
      "name": "bob",
      "age": "21",
      "eyesight": "20/20"
    },
    {
      "name": "julie",
      "age": "27",
      "eyesight": "21/19"
    },
    {
      "name": "mark",
      "age": "42",
      "eyesight": "17/17"
    },
  ]`
  

---

Documentation

If you can read typescript, just look at the source code. It's a single ~250 line file.

This data is used in the examples below

// imagine raw text also found at /path/to/file.csv
const EXAMPLE_DATA = `
a, b
1, 2
x, y
`;

interface IExampleData {
  a: string;
  b: string;
}

Creating Object Arrays

• csvTextToObjectArray(rawCsvText: string)

  Creates an object array from csv. Most useful function, likely. The IExampleData templating is optional.

  const items = csvTextToObjectArray<IExampleData>(EXAMPLE_DATA);
  /* items === [
    {a: "1", b: "2"},
    {a: "x", b: "y"}
  ]*/
  

  
  

• csvFileToObjectArray(csvFilePath: string)

  Asynchronously load a file, turn it into an array of objects. The IExampleData templating is optional.

  const csvLoadPath = path.join(__dirname, "/path/to/file.csv");
  csvFileToObjectArray<IExampleData>(csvLoadPath).then((items) => console.log(items));
  // or
  const items = await csvFileToObjectArray<IExampleData>(csvLoadPath);
  

  
  

• csvFileToObjectArraySync(csvFilePath: string)

  Synchronously load a file, turn it into an array of objects. The IExampleData templating is optional.

  const csvLoadPath = path.join(__dirname, "/path/to/file.csv");
  const items = csvFileToObjectArraySync<IExampleData>(csvLoadPath);
  

Creating 2D String Arrays

• csvTextTo2dArray(rawCsvText: string)

  Creates a 2d array from raw csv text

  const array2d = csvTextTo2dArray(EXAMPLE_DATA);
  /* array2d === [
    ["a", "b"],
    ["1", "2"],
    ["x", "y"],
  ]*/
  

  
  

• csvFileTo2dArray(csvFilePath: string)

  Asynchronously creates a 2d array from a csv file

  const csvLoadPath = path.join(__dirname, "/path/to/file.csv");
  csvFileTo2dArray(csvLoadPath).then((array2d) => console.log(array2d));
  // or
  const array2d = await csvFileTo2dArray(csvLoadPath);
  

  
  

• csvFileTo2dArraySync(csvFilePath: string)

  Synchronously creates a 2d array from a csv file

  const csvLoadPath = path.join(__dirname, "/path/to/file.csv");
  const array2d = csvFileTo2dArraySync(csvLoadPath);
  

Creating JSON string

• csvTextToJsonText(rawCsvText: string)

  Turn raw csv text into json text

  const json = csvTextToJsonText(EXAMPLE_DATA);
  /* json === `[
    {"a": "1", "b": "2"},
    {"a": "x", "b": "y"}
  ]`*/
  

  
  
  
  

Direct conversion from .csv to .json files

• csvFileToJsonFile(csvFilePath: string, jsonSavePath: string)

  Asynchronously load a file, convert it to json, then save it. The IExampleData templating is optional. (optional). You can add a function to parse the object array before saving it

  const csvLoadPath = path.join(__dirname, "/path/to/file.csv");
  const jsonSavePath = path.join(__dirname, "/path/to/output.json")
  csvFileToJsonFile(csvLoadPath, jsonSavePath).then(() => console.log("File saved"))
  
  // or (with conversion)
  await csvFileToJsonFile<IExampleData>(csvLoadPath, jsonSavePath, (items) => {
    items.forEach((it) => it.b = "foo");
    return items;
  });
  

  
  

• csvFileToJsonFileSync(csvFilePath: string, jsonSavePath: string)

  Synchronously load a file, convert it to json, then save it. The IExampleData templating is optional. (optional). You can add a function to parse the object array before saving it

  const csvLoadPath = path.join(__dirname, "/path/to/file.csv");
  const jsonSavePath = path.join(__dirname, "/path/to/output.json")
  csvFileToJsonFileSync(csvLoadPath, jsonSavePath);
  
  // or (with conversion)
  csvFileToJsonFileSync<IExampleData>(csvLoadPath, jsonSavePath, (items) => {
    items.forEach((it) => it.b = "foo");
    return items;
  });
  

Special Cases

• ICsvParserArgs

  All the special setting for the parser.

  interface ICsvParserArgs {
    delimiter?: RegExp | string;
    jsonTabSize?: null | number;
    trimRawText?: boolean;
    convertPrimitives?: boolean | Array<"boolean" | "number" | "array" | "object">,
  }
  

• new CsvParser(args: ICsvParserArgs)

  Create a special csv parser, with custom rules

  const parser = new CsvParser({
    delimeter: "\t",    // now does TSV
    jsonTabSize: 3,     // set to null for one-liner json
  });
  
  const array2d = parser.fileTo2dArraySync("/path/to/file.csv");
  

---

TSV

Search for CsvParser(). It has a delimiter argument.

---

One of the Tests

const testText = `
a,b,c
1,2,3
"list, of, things","a ""tough, ugly, quote""",thing
TRUE,bar,qux
"[1, 2, 3]","{""first"": 1}",false
`

test(`Doesn't break on quotes or commas.  Handles primitives and json.`, async (t) => {
  const array2d = csvTextTo2dArray(testText);
  t.deepEqual(array2d, [
    ["a", "b", "c"],
    [1, 2, 3],
    ["list, of, things", `a "tough, ugly, quote"`, `thing`],
    [true, "bar", `qux`],
    [[1,2,3], {first: 1}, false],
  ])
})

---

Rant

This isn't so much a rant, I'm just going to say I didn't much like the other csv tools. Here's the best two I could find:

• csvtojson

  • Unpacked Size 8.69 MB, Total Files 393, Dependencies 3.
  • Does way too much, difficult to figure how to do simple things.
  • Is cool once you figure it out, I think.

• papaparse

  • Unpacked Size 249kB, Total Files 21, Dependencies 0. 👍
  • First feature is "Easy to use"
  • Doesn't show an example.
  • Doesn't seem to have typescript typings... does it do promises or callbacks?
  • Probably good, but the npm docs just aren't doing it justice..

Then there's like 100 more.