console: add table method

PR-URL: https://github.com/nodejs/node/pull/18137
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

1 files changed, 83 insertions, 0 deletions

diff --git a/lib/internal/cli_table.js b/lib/internal/cli_table.js
new file mode 100644
index 0000000000..4c07d92eeb
--- /dev/null
+++ b/lib/internal/cli_table.js
@@ -0,0 +1,83 @@
+'use strict';
+
+const { Buffer } = require('buffer');
+const { removeColors } = require('internal/util');
+const HasOwnProperty = Function.call.bind(Object.prototype.hasOwnProperty);
+
+const tableChars = {
+  /* eslint-disable node-core/non-ascii-character */
+  middleMiddle: '─',
+  rowMiddle: '┼',
+  topRight: '┐',
+  topLeft: '┌',
+  leftMiddle: '├',
+  topMiddle: '┬',
+  bottomRight: '┘',
+  bottomLeft: '└',
+  bottomMiddle: '┴',
+  rightMiddle: '┤',
+  left: '│ ',
+  right: ' │',
+  middle: ' │ ',
+  /* eslint-enable node-core/non-ascii-character */
+};
+
+const countSymbols = (string) => {
+  const normalized = removeColors(string).normalize('NFC');
+  return Buffer.from(normalized, 'UCS-2').byteLength / 2;
+};
+
+const renderRow = (row, columnWidths) => {
+  let out = tableChars.left;
+  for (var i = 0; i < row.length; i++) {
+    const cell = row[i];
+    const len = countSymbols(cell);
+    const needed = (columnWidths[i] - len) / 2;
+    // round(needed) + ceil(needed) will always add up to the amount
+    // of spaces we need while also left justifying the output.
+    out += `${' '.repeat(needed)}${cell}${' '.repeat(Math.ceil(needed))}`;
+    if (i !== row.length - 1)
+      out += tableChars.middle;
+  }
+  out += tableChars.right;
+  return out;
+};
+
+const table = (head, columns) => {
+  const rows = [];
+  const columnWidths = head.map((h) => countSymbols(h));
+  const longestColumn = columns.reduce((n, a) => Math.max(n, a.length), 0);
+
+  for (var i = 0; i < head.length; i++) {
+    const column = columns[i];
+    for (var j = 0; j < longestColumn; j++) {
+      if (!rows[j])
+        rows[j] = [];
+      const v = rows[j][i] = HasOwnProperty(column, j) ? column[j] : '';
+      const width = columnWidths[i] || 0;
+      const counted = countSymbols(v);
+      columnWidths[i] = Math.max(width, counted);
+    }
+  }
+
+  const divider = columnWidths.map((i) =>
+    tableChars.middleMiddle.repeat(i + 2));
+
+  const tl = tableChars.topLeft;
+  const tr = tableChars.topRight;
+  const lm = tableChars.leftMiddle;
+  let result = `${tl}${divider.join(tableChars.topMiddle)}${tr}
+${renderRow(head, columnWidths)}
+${lm}${divider.join(tableChars.rowMiddle)}${tableChars.rightMiddle}
+`;
+
+  for (const row of rows)
+    result += `${renderRow(row, columnWidths)}\n`;
+
+  result += `${tableChars.bottomLeft}${
+    divider.join(tableChars.bottomMiddle)}${tableChars.bottomRight}`;
+
+  return result;
+};
+
+module.exports = table;