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string width and ansi stripping: working versions (tested 2026-10-16)

Measure the visual width of ASCII, CJK, and emoji strings and strip ANSI escape codes with string-width and strip-ansi, asserting widths and cleaned output offline.

passed6 passed · 0 failed2026-10-16 19:54 UTC
Status
passed
Last passed
2026-10-16 19:54 UTC
Tests
6 / 6
Language
TypeScript
Runtime
node v22.23.3
pinned versions4
string-width@8.3.0strip-ansi@7.2.0@types/node@26.6.5tsx@4.23.15
run it
npm install --no-audit --no-fund --ignore-scripts=false
npm test
test environment
node v22.23.3
linux 6.17.0-1022-azure
x64
runner: github-actions 38958328921

The code

Exactly the files that passed. Your agent can pull them with get_recipe("string-width-strip-ansi") (install), or see them on GitHub.

package.json
{
  "name": "string-width-strip-ansi",
  "private": true,
  "type": "module",
  "scripts": {
    "test": "node --import tsx --test test/*.test.ts"
  },
  "dependencies": {
    "string-width": "8.3.0",
    "strip-ansi": "7.2.0"
  },
  "devDependencies": {
    "@types/node": "26.6.5",
    "tsx": "4.23.15"
  }
}
src/width.ts
import stringWidth from "string-width";
import stripAnsi from "strip-ansi";

export function visibleWidth(input: string): number {
  return stringWidth(input);
}

export function strip(input: string): string {
  return stripAnsi(input);
}

export const RED = "\u001b[31m";
export const BOLD = "\u001b[1m";
export const RESET = "\u001b[0m";

export function colorize(text: string, codes: string[]): string {
  return codes.join("") + text + RESET;
}
test/width.test.ts
import { test } from "node:test";
import assert from "node:assert/strict";
import stringWidth from "string-width";
import stripAnsi from "strip-ansi";
import { RED, BOLD, RESET, visibleWidth, strip, colorize } from "../src/width.ts";

test("measures ASCII width as character count", () => {
  assert.equal(visibleWidth("hello"), 5);
  assert.equal(visibleWidth(""), 0);
});

test("measures CJK wide characters as two columns each", () => {
  assert.equal(visibleWidth("你好"), 4);
  assert.equal(visibleWidth("こんにちは"), 10);
});

test("measures emoji as two columns", () => {
  assert.equal(visibleWidth("👍"), 2);
  assert.equal(visibleWidth("a👍b"), 4);
});

test("ignores ANSI escape codes when measuring width", () => {
  const colored = colorize("hello", [RED]);
  assert.equal(visibleWidth(colored), 5);
  assert.equal(stringWidth(colored), 5);
});

test("strips ANSI codes to plain text", () => {
  const colored = colorize("hello", [BOLD, RED]);
  assert.equal(colored, `${BOLD}${RED}hello${RESET}`);
  assert.equal(strip(colored), "hello");
  assert.equal(stripAnsi(colored), "hello");
});

test("strip keeps wide characters and emoji intact", () => {
  const mixed = colorize("你好👍", [RED]);
  assert.equal(strip(mixed), "你好👍");
  assert.equal(visibleWidth(strip(mixed)), 6);
});

Connect to ProvenPin

Add the free MCP server so your agent can pull this recipe and others like it. Same setup as the docs.

terminal
claude mcp add --transport http provenpin https://mcp.provenpin.com/mcp

Any other MCP client: Streamable HTTP at https://mcp.provenpin.com/mcp. No API key, no signup.