Add regex option to search

[subhajitlucky]

Fixes #11.

Summary

• Adds a .* regex toggle beside the search input.
• Sends regex mode through the webview search message and runs regex-aware matching in SearchService.
• Carries actual match length into result/preview rendering so regex matches are highlighted correctly.
• Adds a small pure matcher test for literal, regex, invalid regex, and zero-length patterns.

Validation

• npm run test:search-pattern
• git diff --check

Note: npm run lint still fails because the repository has no ESLint configuration file for the existing lint script.

[Copilot]

Pull request overview

Adds an optional regex search mode to the extension’s webview search flow, including correct match-length-based highlighting for regex matches and a small matcher-focused test to validate literal/regex behavior.

Changes:

• Added a regex toggle (.*) in the webview and threaded isRegex through the webview message to the extension host search.
• Introduced searchPattern helpers and updated SearchService to use regex-aware matching and to carry matchLength through to the UI for accurate highlighting.
• Added a pure Node test (tests/searchPattern.test.js) plus an npm script to run it.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tests/searchPattern.test.js	Adds basic tests for literal vs regex matching, invalid regex handling, and zero-length match behavior.
src/searchPattern.ts	New helper module to build a search pattern and enumerate matches (index + length).
src/services/SearchService.ts	Switches search implementation to pattern-based matching and forwards match length into SearchMatch.
src/types.ts	Extends search result types with matchLength and adds isRegex to the search webview message.
src/WebviewManager.ts	Threads isRegex into search calls and adjusts search abort tracking.
src/webview/webviewContent.ts	Adds the .* regex toggle button beside the search input.
src/webview/script.ts	Implements regex toggle behavior, includes isRegex in search messages, and updates highlighting to use matchLength.
media/styles.css	Styles the regex toggle alongside the existing filter toggle button.
package.json	Adds test:search-pattern script for running the new matcher test.

Comments suppressed due to low confidence (1)

src/services/SearchService.ts:178

• searchPattern is shared across the Promise.all(...) in searchBatch, but findPatternMatches mutates pattern.expression.lastIndex (and increments it for zero-length matches). Because RegExp objects with the g flag are stateful, running exec loops concurrently across multiple files can cause missed/incorrect matches. Consider cloning/compiling a fresh RegExp per file (or per findPatternMatches call) so each async task has its own non-shared matcher state.

    private async searchBatch(
        batch: vscode.Uri[],
        searchPattern: SearchPattern
    ): Promise<Array<{ filePath: string; matches: SearchMatch[] } | null>> {
        return Promise.all(batch.map(async (file) => {
            try {
                const stat = await vscode.workspace.fs.stat(file);

                if (stat.size > this.options.maxFileSize) {
                    return null;
                }

                const uint8Array = await vscode.workspace.fs.readFile(file);
                const text = new TextDecoder('utf-8', { fatal: false }).decode(uint8Array);

                const matches = this.findMatchesInFile(file, text, searchPattern);
                return matches.length > 0 ? { filePath: file.fsPath, matches } : null;
            } catch (error) {
                return null;
            }
        }));

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[subhajitlucky]

Pushed a follow-up commit (85b96cd) that removes the shared mutable RegExp from SearchPattern. findPatternMatches now creates a fresh RegExp per scan, and the matcher test covers reusable patterns without exposing shared RegExp state.