Kit Langton
47 lines
1.5 KiB
TypeScript
47 lines
1.5 KiB
TypeScript
export * as Bom from "./bom.js"
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import { Effect } from "effect"
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import { FSUtil } from "./fs-util.js"
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const code = 0xfeff
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const value = String.fromCharCode(code)
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export function split(text: string) {
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const stripped = text.replace(/^\uFEFF+/, "")
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return { bom: stripped.length !== text.length, text: stripped }
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}
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export function join(text: string, bom: boolean) {
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const stripped = split(text).text
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return bom ? value + stripped : stripped
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}
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export function has(content: Uint8Array) {
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return content[0] === 0xef && content[1] === 0xbb && content[2] === 0xbf
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}
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export function decodeBytes(content: Uint8Array) {
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return split(decode(content))
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}
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export function syncBytes(content: Uint8Array, bom: boolean) {
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const decoded = decode(content)
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const current = split(decoded)
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const canonical = join(current.text, bom)
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return { text: current.text, bytes: decoded === canonical ? undefined : new TextEncoder().encode(canonical) }
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}
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export const readFile = Effect.fn("Bom.readFile")(function* (fs: FSUtil.Interface, filepath: string) {
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return decodeBytes(yield* fs.readFile(filepath))
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})
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export const syncFile = Effect.fn("Bom.syncFile")(function* (fs: FSUtil.Interface, filepath: string, bom: boolean) {
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const synced = syncBytes(yield* fs.readFile(filepath), bom)
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if (synced.bytes) yield* fs.writeWithDirs(filepath, synced.bytes)
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return synced.text
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})
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function decode(content: Uint8Array) {
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return new TextDecoder("utf-8", { ignoreBOM: true }).decode(content)
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}
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