Simple build-time javascript dependency resolution

file.js

( function() {
  console.log( 'one' );
  //= require two.js
}() );

resolve.sh

#!/usr/bin/env bash

##
# a crude solution for resolving dependencies
#
# this script looks for "//= require foo", and replaces it with the contents
# of the file "foo" inline.  it makes no effort to prevent cyclical
# dependencies, so be careful there.
#

DIRECTIVE="//= require "

function resolve_dependencies {
  local FILE="$1"
  local DIR=$(dirname "$FILE")

  if grep -q "$DIRECTIVE" "$FILE"; then
    cat "$FILE" | while IFS='' read -r LINE; do
      local DEPENDENCY=$(expr "$LINE" : ".*$DIRECTIVE\(.*\)")
      if [[ "$DEPENDENCY" != "" ]]; then
        DEPENDENCY="${DIR}/${DEPENDENCY}"
        if [ -f "$DEPENDENCY" ]; then
          echo -n "${LINE%%$DIRECTIVE*}"
          resolve_dependencies "$DEPENDENCY"
        else
          echo "error: no such file: $DEPENDENCY (required by $FILE)" >&2
          exit 1
        fi
      else
        echo "$LINE"
      fi
    done
  else
    cat "$FILE"
  fi
}

if [[ "$1" == "" ]]; then
  echo "usage: $0 <file.js>" >&2
else
  resolve_dependencies "$1"
fi

resolved.js

( function() {
console.log( 'one' );
console.log( "two" );
}() );

two.js

console.log( "two" );