Runs a js_binary as a build action.

This macro wraps Aspect bazel-lib's run_binary ( and adds attributes and features specific to rules_js's js_binary.

Load this with,

load("@aspect_rules_js//js:defs.bzl", "js_run_binary")

Macros and Functions


Wrapper around @aspect_bazel_lib run_binary that adds convienence attributes for using a js_binary tool.

This rule does not require Bash native.genrule.

Example usage (generated)

load("@aspect_rules_js//js:defs.bzl", "js_run_binary")

    # Target name
    name = "",
    # The tool to run in the action
    tool = None,


Target name


The tool to run in the action.

Should be a js_binary rule. Use Aspect bazel-lib's run_binary ( for other *_binary rule types.


Environment variables of the action.

Subject to $(location) and make variable expansion.


Additional inputs of the action.

These labels are available for $(location) expansion in args and env.


Output files generated by the action.

These labels are available for $(location) expansion in args and env.


Output directories generated by the action.

These labels are not available for $(location) expansion in args and env since they are not pre-declared labels created via attr.output_list(). Output directories are declared instead by ctx.actions.declare_directory.


Command line arguments of the binary.

Subject to $(location) and make variable expansion.


Working directory to run the build action in.

This overrides the chdir value if set on the js_binary tool target.

By default, js_binary tools run in the root of the output tree. For more context on why, please read the aspect_rules_js README

To run in the directory containing the js_run_binary in the output tree, use chdir = package_name() (or if you're in a macro, use native.package_name()).

WARNING: this will affect other paths passed to the program, either as arguments or in configuration files, which are workspace-relative.

You may need ../../ segments to re-relativize such paths to the new working directory.


set to capture the stdout of the binary to a file, which can later be used as an input to another target subject to the same semantics as outs


set to capture the stderr of the binary to a file, which can later be used as an input to another target subject to the same semantics as outs


set to capture the exit code of the binary to a file, which can later be used as an input to another target subject to the same semantics as outs. Note that setting this will force the binary to exit 0.

If the binary creates outputs and these are declared, they must still be created


produce no output on stdout nor stderr when program exits with status code 0.

This makes node binaries match the expected bazel paradigm.


Use the entry_point script of the js_binary tool that is in the execroot output tree instead of the copy that is in runfiles.

Runfiles of tool are all hoisted to srcs of the underlying run_binary so they are included as execroot inputs to the action.

Using the entry point script that is in the execroot output tree means that there will be no conflicting runfiles node_modules in the node_modules resolution path which can confuse npm packages such as next and react that don't like being resolved in multiple node_modules trees. This more closely emulates the environment that tools such as Next.js see when they are run outside of Bazel.

When True, the js_binary tool must have copy_data_to_bin set to True (the default) so that all data files needed by the binary are available in the execroot output tree. This requirement can be turned off with by setting allow_execroot_entry_point_with_no_copy_data_to_bin to True.


When True, all srcs files are copied to the output tree that are not already there.


see js_filegroup documentation


see js_filegroup documentation


see js_filegroup documentation


Set the logging level of the js_binary tool.

This overrides the log level set on the js_binary tool target.


A one-word description of the action, for example, CppCompile or GoLink.


Progress message to show to the user during the build, for example, "Compiling to create foo.o". The message may contain %{label}, %{input}, or %{output} patterns, which are substituted with label string, first input, or output's path, respectively. Prefer to use patterns instead of static strings, because the former are more efficient.


Information for scheduling the action.

For example,

execution_requirements = {
    "no-cache": "1",

See for useful keys.


Whether to include build status files as inputs to the tool. Possible values:

  • stamp = 0 (default): Never include build status files as inputs to the tool. This gives good build result caching. Most tools don't use the status files, so including them in --stamp builds makes those builds have many needless cache misses. (Note: this default is different from most rules with an integer-typed stamp attribute.)
  • stamp = 1: Always include build status files as inputs to the tool, even in --nostamp builds. This setting should be avoided, since it is non-deterministic. It potentially causes remote cache misses for the target and any downstream actions that depend on the result.
  • stamp = -1: Inclusion of build status files as inputs is controlled by the --[no]stamp flag. Stamped targets are not rebuilt unless their dependencies change.

Default value is 0 since the majority of js_run_binary targets in a build graph typically do not use build status files and including them for all js_run_binary actions whenever --stamp is set would result in invalidating the entire graph and would prevent cache hits. Stamping is typically done in terminal targets when building release artifacts and stamp should typically be set explicitly in these targets to -1 so it is enabled when the --stamp flag is set.

When stamping is enabled, an additional two environment variables will be set for the action: - BAZEL_STABLE_STATUS_FILE - BAZEL_VOLATILE_STATUS_FILE

These files can be read and parsed by the action, for example to pass some values to a bundler.


Patch the to Node.js fs API ( for this node program to prevent the program from following symlinks out of the execroot, runfiles and the sandbox.

When enabled, js_binary patches the Node.js sync and async fs API functions lstat, readlink, realpath, readdir and opendir so that the node program being run cannot resolve symlinks out of the execroot and the runfiles tree. When in the sandbox, these patches prevent the program being run from resolving symlinks out of the sandbox.

When disabled, node programs can leave the execroot, runfiles and sandbox by following symlinks which can lead to non-hermetic behavior.


Turn off validation that the js_binary tool has copy_data_to_bin set to True when use_execroot_entry_point is set to True.

See use_execroot_entry_point doc for more info.


Additional arguments