Kjell Tore Guttormsen
c6ff4fa94a
Step 3 of plan.md (Spor B B3 pipeline run). Adds one line under Options: in the HELP template literal so --help users can discover the new flag. Satisfies SC #8. [skip-docs]
93 lines
3 KiB
JavaScript
Executable file
93 lines
3 KiB
JavaScript
Executable file
#!/usr/bin/env node
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import { readFileSync } from 'node:fs';
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const HELP = `Usage: tally [options] <pattern> <file>
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Count literal-substring occurrences of <pattern> in <file>.
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Options:
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-i, --ignore-case Case-insensitive matching
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--lines Count lines containing pattern (not total occurrences)
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-r, --regex Interpret <pattern> as a JavaScript regular expression
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--json Emit a JSON object on stdout
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-h, --help Show this help and exit
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Exit codes: 0=success 1=file error 2=invalid argv
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`;
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function fail(msg, code = 2) {
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process.stderr.write(`tally: ${msg}\n`);
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process.exit(code);
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}
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function parseArgs(argv) {
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const positional = [];
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const flags = { json: false, ignoreCase: false, lines: false, regex: false };
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for (const a of argv) {
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if (a === '--json') flags.json = true;
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else if (a === '-i' || a === '--ignore-case') flags.ignoreCase = true;
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else if (a === '--lines') flags.lines = true;
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else if (a === '--regex' || a === '-r') flags.regex = true;
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else if (a === '-h' || a === '--help') { process.stdout.write(HELP); process.exit(0); }
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else if (a.startsWith('-')) fail(`unknown flag: ${a}`);
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else positional.push(a);
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}
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if (positional.length !== 2) fail('expected <pattern> <file>');
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return { pattern: positional[0], file: positional[1], flags };
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}
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function compileRegex(pattern) {
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try { return new RegExp(pattern, 'g'); }
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catch (e) { fail(`invalid regex: ${e.message}`); }
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}
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function countOccurrences(text, pattern, ignoreCase) {
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if (pattern.length === 0) return 0;
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const haystack = ignoreCase ? text.toLowerCase() : text;
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const needle = ignoreCase ? pattern.toLowerCase() : pattern;
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let count = 0, idx = 0;
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while ((idx = haystack.indexOf(needle, idx)) !== -1) { count++; idx += needle.length; }
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return count;
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}
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function countLines(text, pattern, ignoreCase) {
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if (pattern.length === 0) return 0;
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const needle = ignoreCase ? pattern.toLowerCase() : pattern;
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let count = 0;
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for (const line of text.split('\n')) {
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const haystack = ignoreCase ? line.toLowerCase() : line;
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if (haystack.includes(needle)) count++;
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}
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return count;
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}
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function main() {
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const { pattern, file, flags } = parseArgs(process.argv.slice(2));
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let text;
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try {
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text = readFileSync(file, 'utf8');
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} catch (err) {
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const what = err.code === 'ENOENT' ? 'file not found' : 'read error';
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process.stderr.write(`tally: ${what}: ${file}\n`);
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process.exit(1);
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}
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let count;
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if (flags.regex) {
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const re = compileRegex(pattern);
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count = (text.match(re) || []).length;
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} else if (flags.lines) {
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count = countLines(text, pattern, flags.ignoreCase);
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} else {
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count = countOccurrences(text, pattern, flags.ignoreCase);
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}
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if (flags.json) {
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process.stdout.write(JSON.stringify({
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pattern, file, count,
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flags: { json: flags.json, ignoreCase: flags.ignoreCase, lines: flags.lines, regex: flags.regex },
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}) + '\n');
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} else {
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process.stdout.write(count + '\n');
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}
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}
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main();
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