Module

The require function is always available there is no need to import module explicitly.

require(id)

  • id {string} Module name to be loaded.

Loads the module named id.

Example

  1. var assert = require('assert');
  3. assert.equal(2, 2);

Loading a module

If a native module named id exists, load it and return. (Native module: which module came from the IoT.js itself)

require function searches for modules in the following order:

  1. Current working directory.
  2. iotjs_modules folder under current working directory.
  3. $HOME/iotjs_modules
  4. $IOTJS_PATH/iotjs_modules
  5. $IOTJS_EXTRA_MODULE_PATH

For each directory in search paths above:

  • If a file id exists, load it and return.
  • If a file id.js exists, load it and retun.
  • If a directory id exists, module system consider the directory as a package:
    • If id/package.json contains main property, load the file named main property.
    • If id/package.json exists, but neither the main property nor the file named main property exist, load index.js.
  • Extra step for Linux/Tizen targets:
    • If a file with id.node exists, try to load it as an N-API native addon and return.

Changing current working directory

You can explicitly change current working directory by setting IOTJS_WORKING_DIR_PATH environment variable. It is not recommended that you set this variable, if possible.

Adding extra paths for module loading

In order to add more directories to look for modules, you can set IOTJS_EXTRA_MODULE_PATH as an environment variable of your system. For instance, ./node_modules and ./my_modules will be referred if they’re declared as follows.

IOTJS_EXTRA_MODULE_PATH=./node_modules:./my_modules