# linegauge > Every export of linegauge, with its signature and doc comment: lineCount, measure, width, width, strip, truncate and 3 more, plus 4 types. Source: https://linegauge.interlace.tools/docs/api linegauge — how much of a terminal line a string occupies, and how to fold it. F1 of the foundation tier, built by moving rather than by writing: `width` and `wrap` were already in `flagstaff`, already ported, already graded differentially against `string-width` and `wrap-ansi`. This package is where they belong, because measuring a line is not drawing one — a spinner, a box, a table and a status line all need the measurement, and nothing about the measurement needs any of them. The default export is `width`, byte-for-byte call-compatible with `string-width`'s default (R8), so `overrides: { "string-width": "npm:linegauge@^1" }` resolves. `slice`, `truncate` and `widest` came next, built on the style stack `wrap` already carried — which is the consolidation the design is named for: `slice-ansi`, `wrap-ansi` and `cli-truncate` each keep their own copy of it, and they disagree at the edges. `strip` (R3) followed, and it is where the measured divergence from Node's own `stripVTControlCharacters` is recorded — one shape in sixteen, and it was a live bug in `width()`. R2's fast path: locked by `differential.test.ts`. ```ts import width from 'linegauge'; import { lineCount, measure, width, … } from 'linegauge'; ``` ## Functions ### default The default export, declared as `width`. How many terminal columns `input` occupies once its escape sequences are removed. **Non-strings measure 0.** `string-width` has always answered `0` for a number, `null` or `undefined` rather than throwing, and callers rely on it — a width function is usually reached with whatever a template produced. Three cases of its suite grade exactly this, and the check is `typeof` rather than a truthiness test so that `0` and `false` are not quietly treated as strings that happen to be empty. ```ts function width(input: string, options?: WidthOptions): number; ``` | Parameter | Type | | :-- | :-- | | `input` | `string` | | `options` (optional) | `WidthOptions` | **Returns** `number` ### lineCount Lines a string occupies in a terminal `columns` wide — the measurement the frame loop actually asks for. An empty line still occupies one. ```ts function lineCount(text: string, columns: number): number; ``` | Parameter | Type | | :-- | :-- | | `text` | `string` | | `columns` | `number` | **Returns** `number` ### measure Columns a string of *plain* text occupies — no escape scan. The wrapper below has already split its input into text runs and complete sequences, so rescanning would only give a malformed sequence a second chance to be mistaken for one. ```ts function measure(text: string, ambiguousIsWide?: boolean): number; ``` | Parameter | Type | | :-- | :-- | | `text` | `string` | | `ambiguousIsWide` (optional) | `boolean` | **Returns** `number` ### width How many terminal columns `input` occupies once its escape sequences are removed. **Non-strings measure 0.** `string-width` has always answered `0` for a number, `null` or `undefined` rather than throwing, and callers rely on it — a width function is usually reached with whatever a template produced. Three cases of its suite grade exactly this, and the check is `typeof` rather than a truthiness test so that `0` and `false` are not quietly treated as strings that happen to be empty. ```ts function width(input: string, options?: WidthOptions): number; ``` | Parameter | Type | | :-- | :-- | | `input` | `string` | | `options` (optional) | `WidthOptions` | **Returns** `number` ## Interfaces ### Options What `width` accepts beyond the string. Graded against `string-width`'s own suite, so the names and the defaults are its names and its defaults, not ours. ```ts interface WidthOptions { /** * Treat East Asian Ambiguous characters as one column. **Default `true`** — the incumbent's * default, and right for a Latin terminal: `±`, `×`, `÷`, the box-drawing set, Greek and * Cyrillic all occupy one column there. * * `false` for a CJK context, where a terminal using a CJK font renders the same characters * two columns wide. Nothing can detect which a terminal is doing, which is exactly why this * is the caller's decision and not ours. */ ambiguousIsNarrow?: boolean; /** * Count escape sequences as the characters they are made of instead of removing them. * * Off by default, which is what every caller measuring styled output wants. On, the escape * byte itself is still non-printing — `\u001B[31m` measures 4, the `[31m` a terminal would * have swallowed. */ countAnsiEscapeCodes?: boolean; } ``` ### WidthOptions What `width` accepts beyond the string. Graded against `string-width`'s own suite, so the names and the defaults are its names and its defaults, not ours. ```ts interface WidthOptions { /** * Treat East Asian Ambiguous characters as one column. **Default `true`** — the incumbent's * default, and right for a Latin terminal: `±`, `×`, `÷`, the box-drawing set, Greek and * Cyrillic all occupy one column there. * * `false` for a CJK context, where a terminal using a CJK font renders the same characters * two columns wide. Nothing can detect which a terminal is doing, which is exactly why this * is the caller's decision and not ours. */ ambiguousIsNarrow?: boolean; /** * Count escape sequences as the characters they are made of instead of removing them. * * Off by default, which is what every caller measuring styled output wants. On, the escape * byte itself is still non-printing — `\u001B[31m` measures 4, the `[31m` a terminal would * have swallowed. */ countAnsiEscapeCodes?: boolean; } ``` ## Re-exported Documented on the page of the entry point that declares them. | Export | Kind | Documented in | | :-- | :-- | :-- | | `slice` | function | [`linegauge/slice`](/docs/api/slice#slice) | | `strip` | function | [`linegauge/strip`](/docs/api/strip#strip) | | `truncate` | function | [`linegauge/truncate`](/docs/api/truncate#truncate) | | `widest` | function | [`linegauge/widest`](/docs/api/widest#widest) | | `wrap` | function | [`linegauge/wrap`](/docs/api/wrap#wrap) | | `TruncateOptions` | interface | [`linegauge/truncate`](/docs/api/truncate#truncateoptions) | | `WrapOptions` | interface | [`linegauge/wrap`](/docs/api/wrap#wrapoptions) |