Make row splitting code more readable

Author: oskarhane

src/ascii-data-table.js

@@ -2,7 +2,8 @@ import * as R from './functions'
 import repeat from 'core-js/library/fn/string/repeat'
 
 const len = (val) => typeof val === 'undefined' ? 0 : ('' + val).length
-const padString = (character, width) => !width ? '' : repeat(character, width)
+const padString = (character) => (width) => !width ? '' : repeat(character, width)
+const spacePad = padString(' ')
 const stringifyRows = (rows) => {
   if (!Array.isArray(rows) || !rows.length) return []
   return rows.map((row) => row.map(JSON.stringify))
@@ -14,7 +15,7 @@ const getThinSeparatorLine = (colWidths) => getSeparatorLine('─', '├', '┼'
 const getBottomSeparatorLine = (colWidths) => getSeparatorLine('─', '└', '┴', '┘', colWidths)
 const getSeparatorLine = (horChar, leftChar, crossChar, rightChar, colWidths) => {
   return leftChar + colWidths.map(function (w) {
-    return padString(horChar, w)
+    return padString(horChar)(w)
   }).join(crossChar) + rightChar
 }
 
@@ -37,22 +38,22 @@ const rowHeights = (maxWidth, input) => {
   })
 }
 
-const splitRowsToLines = (maxWidth, heights, widths, input) => {
+const rowsToLines = (maxWidth, heights, widths, input) => {
+  const columnToLinesWidths = columnToLines(widths, maxWidth)
   return input.map((row, i) => {
-    return row.map((col, colIndex) => {
-      let lines = R.splitEvery(maxWidth, col)
-      const lastLinesLen = len(R.last(lines))
-      if (lastLinesLen < widths[colIndex]) {
-        lines[lines.length - 1] = lines[lines.length - 1] + padString(' ', widths[colIndex] - lastLinesLen)
-      }
-      while (lines.length < heights[i]) {
-        lines = [].concat(...lines, [padString(' ', widths[colIndex])])
-      }
-      return lines
-    })
+    return row.map(columnToLinesWidths(heights[i]))
   })
 }
 
+const columnToLines = (widths, maxWidth) => (rowHeight) => (col, colIndex) => {
+  let lines = R.splitEvery(maxWidth, col)
+  lines[lines.length - 1] += spacePad(widths[colIndex] - len(R.last(lines)))
+  while (lines.length < rowHeight) {
+    lines.push(spacePad(widths[colIndex]))
+  }
+  return lines
+}
+
 const createLines = (rows) => {
   return rows.reduce((lines, row) => {
     if (!Array.isArray(row)) {
@@ -63,14 +64,14 @@ const createLines = (rows) => {
   }, [])
 }
 
-const renderForWidth = (rows, maxColWidth = 30, minColWidth = 3) => {
+const main = (rows, maxColWidth = 30, minColWidth = 3) => {
   if (!Array.isArray(rows) || !rows.length) {
     return ''
   }
   maxColWidth = parseInt(maxColWidth)
   const widths = colWidths(maxColWidth, minColWidth, rows)
   const heights = rowHeights(maxColWidth, rows)
-  const norm = splitRowsToLines(maxColWidth, heights, widths, rows)
+  const norm = rowsToLines(maxColWidth, heights, widths, rows)
   const header = createLines(R.head(norm))
   const separated = R.intersperse(getThinSeparatorLine(widths), R.tail(norm))
   const lines = createLines(separated)
@@ -85,7 +86,7 @@ const renderForWidth = (rows, maxColWidth = 30, minColWidth = 3) => {
 
 export default {
   serializeData: (rows) => stringifyRows(rows),
-  tableFromSerializedData: (serializedRows, maxColumnWidth = 30) => renderForWidth(serializedRows, maxColumnWidth),
-  table: (rows, maxColumnWidth = 30) => renderForWidth(stringifyRows(rows), maxColumnWidth),
+  tableFromSerializedData: (serializedRows, maxColumnWidth = 30) => main(serializedRows, maxColumnWidth),
+  table: (rows, maxColumnWidth = 30) => main(stringifyRows(rows), maxColumnWidth),
   maxColumnWidth: (rows) => R.apply(Math.max, colWidths(0, 0, stringifyRows(rows)))
 }