flatten_object.ts

function trimNewlinesAndSpaces(inputString: string | number) {
  // Remove newlines and replace multiple spaces with a single space
  if (typeof inputString === "string") {
    return inputString.replace(/\n/g, '').replace(/ +/g, ' ').replace(/\,/g, '');
  } else {
    return "" + inputString
  }
}

export const flattenObj = (results: any, parentKey: string, obj: any): any => {
  for (let key in obj) {
    // console.log("key> ", key, obj[key], typeof obj[key])
    let newKey = parentKey ? `${parentKey}.${key}` : key;
    if (typeof obj[key] === "string" || typeof obj[key] === "number") {
      results[newKey] = results[newKey] || [];
      results[newKey].push(trimNewlinesAndSpaces(obj[key]))
    } else {
      if (Array.isArray(obj[key])) {
        let numbersOrStrings = obj[key].filter((item: any) => typeof item === "string" || typeof item === "number")
        results[newKey] = results[newKey] || [];
        results[newKey] = results[newKey].concat(numbersOrStrings.map(trimNewlinesAndSpaces))

        let otherObjects = obj[key].filter((item: any) => typeof item !== "string" && typeof item !== "number")
        otherObjects.map(flattenObj.bind(null, results, newKey))
      }
    }
  }
  return results;
};

export const flatObjectToCsvLines = (opts: any, data: any) => {
  let longestArray = -1
  for (let key in data) {
    if (data[key].length > longestArray) {
      longestArray = data[key].length + 1
    }
  }

  let columns = []
  for (let key in data) {
    // if (data[key].length > 0) {
    let row = new Array(longestArray).fill('')
    row[0] = key
    for (let i = 0; i < data[key].length; i++) {
      row[i + 1] = data[key][i]
    }
    columns.push(row)
    // }
  }

  let lines = []
  for (let a = 0; a < longestArray; a++) {
    let line = []
    for (let j = 0; j < columns.length; j++) {
      line.push(columns[j][a])
    }
    lines.push(line)
  }

  if(opts.skipHeader) {
    lines.shift()
  }

  return lines.join("\n")
}

export function getMaxHeaders(objects: any[]) {
  let allHeaders = [] as string[]
  for (let obj of objects) {
    let headers = Object.keys(obj)
    for (let header of headers) {
      if (!allHeaders.includes(header)) {
        allHeaders.push(header)
      }
    }
  }
  return allHeaders
}

export function tidyObject(allHeaders: string[], obj: any) {
  let newObj = {} as any
  for(let header of allHeaders) {
    if(!obj[header]) {
      newObj[header] = []
    } else {
      newObj[header] = obj[header]
    }
  }
  return newObj
}


if (require.main === module) {
  let input1 = {
    "name": "John",
    "age": 30,
    "cars": [{
      "brand": "Ford",
      "km": 5000,
    }]
  }
  let input2 = {
    "name": "Mari",
    "age": 31,
    "pets": [
      {
        "animal": "dog",
        "name": "Fido"
      },
      {
        "animal": "cat",
        "name": "Felix"
      }
    ]
  }

  let flatenedObjects = []

  flatenedObjects.push(flattenObj({}, "", input1))
  flatenedObjects.push(flattenObj({}, "", input2))

  // console.log("flatenedObjects", flatenedObjects)

  let maxHeaders = getMaxHeaders(flatenedObjects)

  // console.log("maxHeaders", maxHeaders)

  flatenedObjects = flatenedObjects.map(tidyObject.bind(null, maxHeaders))

  console.log(flatenedObjects)
  console.log(flatenedObjects.map(flatObjectToCsvLines))

}