transforms.text callback parameters
transforms.text callback receives { content, text }. No parser is used - string in, string out.
Svelte · CLI and AI tooling · all subjects
sv-utils
18 notes, read out of this brain and free to use. Each one was extracted from a source and is re-checked against its exam.
Aborting a transform
Return false from any transform callback to abort. The original content is returned unchanged.
sv-utils is experimental
@sveltejs/sv-utils is currently experimental. The API may change.
sv-utils installation
Install @sveltejs/sv-utils with: npm install -D @sveltejs/sv-utils
transforms.script callback parameters
transforms.script callback receives { ast, comments, content, js }.
transforms.svelte callback parameters
transforms.svelte callback receives { ast, content, svelte, js }.
transforms.svelteScript callback parameters
transforms.svelteScript callback receives { ast, content, svelte, js } where ast.instance is guaranteed to be non-null. Pass { language } as the first argument.
transforms.css callback parameters
transforms.css callback receives { ast, content, css }.
transforms.json callback parameters
transforms.json callback receives { data, content, json }. Mutate the data object directly.
transforms.yaml and transforms.toml callback parameters
transforms.yaml and transforms.toml callbacks receive { data, content }.
transforms are curried functions
Transforms are curried functions. Call them with the callback, then apply to content: const transform = transforms.script(callback); const result = transform(content);
parse API low-level usage
Low-level parse API returns { ast, generateCode } for script, svelte, css, and html. Returns { data, generateCode } for json, yaml, and toml. Usage: import { parse } from '@sveltejs/sv-utils'; const { ast, generateCode } = parse.script(content);
Language tooling namespaces
sv-utils provides namespaced helpers for AST manipulation: js.* for imports/exports/objects/arrays/variables/functions/vite/SvelteKit; css.* for rules/declarations/at-rules/imports; svelte.* for ensureScript/addSlot/addFragment; json.* for arrayUpsert/packageScriptsUpsert; html.* for attribute manipulation; text.* for upsert lines in flat files.
Svelte config location
The svelte/kit config can live in two places: passed to the sveltekit() plugin in vite.config.{js,ts}, or as a default export in svelte.config.{js,ts}. Projects created by sv keep config inside vite.config.js and ship no svelte.config.js.
svelteConfig option nesting rules
Svelte-level options (compilerOptions, preprocess, extensions, vitePlugin) sit on the config object. Kit options (adapter, alias, files, typescript, etc.) are flattened onto the sveltekit() argument in a vite config, or nested under kit in a svelte.config.
svelteConfig.edit method
svelteConfig.edit({ sv, cwd }, callback) allows add-ons to read and edit svelte config. The callback receives { ast, property, override, js }. Use property(name, { fallback }) to get-or-create an option's value, and override(props, { dropLeadingComments }) to set/replace options.
svelteConfig.find and svelteConfig.read methods
svelteConfig.find(read) returns { path, kind } or null (kind is 'vite' or 'svelte'; svelte.config wins when both present). svelteConfig.read(read) locates and parses in one pass, returning { location, config, kit } (the object expressions) or null.
pnpm.allowBuilds helper
pnpm.allowBuilds(packageName) returns a transform for pnpm-workspace.yaml. For pnpm >= 11: writes to unified allowBuilds map ({ pkg: true }), migrating legacy onlyBuiltDependencies list. For pnpm < 11: writes to legacy onlyBuiltDependencies list.