Excluding files from coverage when using Mocha and Istanbul

You can ignore files matching a certain pattern using the -x parameter.

 istanbul help cover ... -x <exclude-pattern> [-x <exclude-pattern>]        one or more fileset patterns e.g. "**/vendor/**" ...

If you run istanbul help config you'll see istanbul's default configuration. You can copy/paste the default config into a .istanbul.yml file at the root of your source tree, then store the exclusions in it.

Here's what mine looks like (this makes it easy to exclude many directories):

verbose: falseinstrumentation:    root: .    extensions:        - .js    default-excludes: true    excludes: ['**/tinymce/**', '**/lib/**', '**/tools/**', '**/build/**']    embed-source: false    variable: __coverage__    compact: true    preserve-comments: false    complete-copy: false    save-baseline: false    baseline-file: ./coverage/coverage-baseline.json    include-all-sources: true    include-pid: false    es-modules: falsereporting:    print: summary    reports:        - lcov    dir: ./tools/coverage    watermarks:        statements: [50, 80]        lines: [50, 80]        functions: [50, 80]        branches: [50, 80]    report-config:        clover: {file: clover.xml}        cobertura: {file: cobertura-coverage.xml}        json: {file: coverage-final.json}        json-summary: {file: coverage-summary.json}        lcovonly: {file: lcov.info}        teamcity: {file: null, blockName: Code Coverage Summary}        text: {file: null, maxCols: 0}        text-lcov: {file: lcov.info}        text-summary: {file: null}hooks:    hook-run-in-context: false    post-require-hook: null    handle-sigint: falsecheck:    global:        statements: 0        lines: 0        branches: 0        functions: 0        excludes: []    each:        statements: 0        lines: 0        branches: 0        functions: 0        excludes: []

I your case I would use the following:

istanbul -x "**/pattern/to/exclude/**" cover _mocha -- --recursive -R tap test/ > test.tap && istanbul report clover –  snoof 9 hours ago 

You can exclude multiple patterns just by adding multiple -x options.