Performance of calculateCellHeights

src/calculateCellHeight.ts

@@ -1,10 +1,31 @@
-import {
-  wrapCell,
-} from './wrapCell';
+import stripAnsi from "strip-ansi";
 
 /**
  * Calculates height of cell content in regard to its width and word wrapping.
  */
 export const calculateCellHeight = (value: string, columnWidth: number, useWrapWord = false): number => {
-  return wrapCell(value, columnWidth, useWrapWord).length;
+  if (value.length === 0) {
+    return 1;
+  }
+  const strippedValue = stripAnsi(value);
+  const size = Math.max(1, columnWidth);
+
+  const pattern = useWrapWord ?
+    new RegExp(`(.{0,${size - 1}}(?:(?:.\\s|[\\\\\\/_\\.,;-]|.$))|.{0,${size}}\\s?)`, 'g') :
+    new RegExp(`(.{0,${size}}\\s*)`, 'g');
+
+  let count = 0;
+  let match;
+
+  while ((match = pattern.exec(strippedValue)) !== null) {
+    if (match[0] || match.index === strippedValue.length && strippedValue.endsWith('\n')) {
+      count++;
+    }
+
+    if (match.index === pattern.lastIndex) {
+      pattern.lastIndex++;
+    }
+  }
+
+  return count || 1;
 };

test/calculateRowHeights.ts

@@ -1,5 +1,8 @@
 /* eslint-disable max-nested-callbacks */
 
+import {
+  performance,
+} from 'perf_hooks';
 import {
   expect,
 } from 'chai';
@@ -72,4 +75,30 @@ describe('calculateRowHeights', () => {
       });
     });
   });
+  context('performance', () => {
+    it('processes 1000 rows with 100 newlines each in under 100 ms', () => {
+      const data = Array.from({length: 1_000}, () => {
+        return ['!', '?\n'.repeat(100)];
+      });
+
+      const config = makeTableConfig(data, {
+        columns: {
+          0: {
+            width: 10,
+            wrapWord: false,
+          },
+        },
+      });
+
+      const startTime = performance.now();
+      const rowHeights = calculateRowHeights(data, config);
+      const endTime = performance.now();
+
+      const executionTime = endTime - startTime;
+
+      expect(executionTime).to.be.lessThan(50);
+      expect(rowHeights).to.have.length(1_000);
+      expect(rowHeights[0]).to.equal(101);
+    });
+  });
 });