import assert from "node:assert";
import { describe, it } from "node:test";
import { normalizeTerminalOutput, truncateToWidth, visibleWidth } from "../src/utils.js";
describe("truncateToWidth", () => {
it("keeps output within width for very large unicode input", () => {
const text = "🙂界".repeat(100_000);
const truncated = truncateToWidth(text, 40, "…");
assert.ok(visibleWidth(truncated) <= 40);
assert.strictEqual(truncated.endsWith("…"), true);
assert.doesNotMatch(truncated, /\x1b\[0m/);
});
it("does not add ANSI resets when truncating plain text", () => {
assert.strictEqual(truncateToWidth("abcdef", 4, ""), "abcd");
assert.strictEqual(truncateToWidth("abcdef", 4, "…"), "abc…");
});
it("preserves ANSI styling for kept text and resets before and after ellipsis", () => {
const text = `\x1b[31m${"hello ".repeat(1000)}\x1b[0m`;
const truncated = truncateToWidth(text, 20, "…");
assert.ok(visibleWidth(truncated) <= 20);
assert.strictEqual(truncated.includes("\x1b[31m"), true);
assert.strictEqual(truncated.endsWith("\x1b[0m…\x1b[0m"), true);
});
it("handles malformed ANSI escape prefixes without hanging", () => {
const text = `abc\x1bnot-ansi ${"🙂".repeat(1000)}`;
const truncated = truncateToWidth(text, 20, "…");
assert.ok(visibleWidth(truncated) <= 20);
});
it("clips wide ellipsis safely without adding resets to plain text", () => {
assert.strictEqual(truncateToWidth("abcdef", 1, "🙂"), "");
assert.strictEqual(truncateToWidth("abcdef", 2, "🙂"), "🙂");
assert.ok(visibleWidth(truncateToWidth("abcdef", 2, "🙂")) <= 2);
});
it("returns the original text when it already fits even if ellipsis is too wide", () => {
assert.strictEqual(truncateToWidth("a", 2, "🙂"), "a");
assert.strictEqual(truncateToWidth("界", 2, "🙂"), "界");
});
it("pads truncated output to requested width", () => {
const truncated = truncateToWidth("🙂界🙂界🙂界", 8, "…", true);
assert.strictEqual(visibleWidth(truncated), 8);
});
it("adds a trailing reset when truncating without an ellipsis", () => {
const truncated = truncateToWidth(`\x1b[31m${"hello".repeat(100)}`, 10, "");
assert.ok(visibleWidth(truncated) <= 10);
assert.strictEqual(truncated.endsWith("\x1b[0m"), true);
});
it("keeps a contiguous prefix instead of skipping a wide grapheme and resuming later", () => {
const truncated = truncateToWidth("🙂\t界 \x1b_abc\x07", 7, "…", true);
assert.strictEqual(truncated, "🙂\t… ");
});
});
describe("visibleWidth", () => {
it("counts tabs inline and skips ANSI inline", () => {
assert.strictEqual(visibleWidth("\t\x1b[31m界\x1b[0m"), 5);
});
it("keeps Thai and Lao AM clusters at their normal cell width", () => {
assert.strictEqual(visibleWidth("ำ"), 1);
assert.strictEqual(visibleWidth("ຳ"), 1);
assert.strictEqual(visibleWidth("กำ"), 2);
assert.strictEqual(visibleWidth("ກຳ"), 2);
});
it("normalizes Thai and Lao AM vowels only for terminal output", () => {
assert.strictEqual(normalizeTerminalOutput("ำ"), "ํา");
assert.strictEqual(normalizeTerminalOutput("ຳ"), "ໍາ");
assert.strictEqual(visibleWidth(normalizeTerminalOutput("ำabc")), visibleWidth("ำabc"));
assert.strictEqual(visibleWidth(normalizeTerminalOutput("ຳabc")), visibleWidth("ຳabc"));
});
});