tstraverse

    0.2.0 • Public • Published

    TSTraverse

    TSTraverse is a Typescript AST traversal tool for making static analysis tools easier to build. As time goes along, helper tooling will be added to limit the need for interacting directly with the typescript library for common tasks.

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    Example

    Basic AST traversal

    // Test to verify enter and leave occur as a matched set
     
    const sourceTree = typescript.createSourceFile(
                'Sample.ts',
                sourceCode,
                typescript.ScriptTarget.ES2015,
                true,
                typescript.compilerOptions);
     
    let nodeStack = [];
    let isMatching = true;
     
    // Enter function will be executed as each node is first interacted with
    function enter(node) {
        nodeStack.push(node);
    }
     
    // Leave function will be executed after all children have been interacted with
    function leave(node) {
        const topNode = nodeStack.pop();
        
        isMatching = isMatching && topNode === node;
    }
     
    // Source tree can start from any known TS node 
    tstraverse.traverse(sourceTree, {
        enter: enter,
        leave: leave
    });
     
    assert.isTrue(isMatching);

    Parsing a source string

    // This is just loading a source code into memory as a string. Source could come from any
    // source as long as it is a single, contiguous string
    const sourceCode = fs.readFileSync('./tests/fixtures/Sample.ts', { encoding: 'utf8' });
    const fileName = 'Sample.ts';
     
    // sourceCode string is required, fileName is optional. The output will only be
    // minimally different -- only the fileName property will vary
    sourceFile = tstraverse.helpers.parse(sourceCode, fileName);

    Comparing syntax kinds

    // Select a node from the AST generated by the parse function
    const firstMember = sourceFile.statements[0].members[0];
    // Select the correct SyntaxKind string from an enum
    const syntaxKind = typescript.SyntaxKind[firstMember.kind];
     
    // This is the actual check between syntax kinds
    const nodeKindMatches = tstraverse.helpers.matchesSyntaxKind(syntaxKind)(firstMember);
     
    // This is from the original test
    assert.isTrue(nodeKindMatches);

    Roadmap

    • Source string -> AST generator for quick parsing
    • Node "syntaxKind" comparison function
    • Quick node line and character start and end coordinate function
    • Other utilities as they bubble up

    Version History

    v0.1.0

    • First traversal functionality added

    v0.2.0

    Added new functionality:

    • AST quick parsing
    • SyntaxKind comparison function

    Install

    npm i tstraverse

    DownloadsWeekly Downloads

    3

    Version

    0.2.0

    License

    MPL-2.0

    Unpacked Size

    28.8 kB

    Total Files

    13

    Last publish

    Collaborators

    • cmstead