Code Reusability: Export and Import

This functionality only works with schemas written in JavaScript, not YAML.

In Cube, your data schema is code, and code is much easier to manage when it is in small, digestible chunks. It is best practice to keep files small and containing only relevant and non-duplicated code. As your data schema grows, maintaining and debugging is much easier with a well-organized codebase.

Cube schemas in JavaScript supports ES6-style export and import statements, which allow writing code in one file and sharing it, so it can be used by another file or files.

There are several typical use cases in Cube where it is considered best practice to extract some variables or functions and then import it when needed.

Quite often, you may want to have an array of test user IDs to exclude from your analysis. You can define it once and export it like this:

// in constants.js
export const TEST_USER_IDS = [1, 2, 3, 4, 5];

Later, you can import into the cube whenever needed:

// in Users.js
import { TEST_USER_IDS } from './constants';

cube(`Users`, {
  sql: `...`,
  measures: {
    /* ... */
  },

  dimensions: {
    /* ... */
  },

  segments: {
    excludeTestUsers: {
      sql: `${CUBE}.id NOT IN (${TEST_USER_IDS.join(', ')})`,
    },
  },
});

You can assign some commonly used SQL snippets to JavaScript functions. The example below shows a parsing helper function, which can be used across any number of cubes to correctly parse a date if it was stored as a string.

You can read more about working with string time dimensions here.

// in helpers.js
export const parseDateWithTimeZone = (column) =>
  `PARSE_TIMESTAMP('%F %T %Ez', ${column})`;
// in events.js
import { parseDateWithTimeZone } from './helpers';

cube(`Events`, {
  sql: `SELECT * FROM events`,

  // ...

  dimensions: {
    date: {
      sql: `${parseDateWithTimeZone('date')}`,
      type: `time`,
    },
  },
});

You may need to import from parent directories as Cube flattens nested directories. The example below shows a correct way to import a helper function, which is located in a parent directory.

.
├── README.md
├── cube.js
├── package.json
└── schema
    ├── utils.js
    └── Sales
        └── Orders.js
// in schema/Sales/Orders.js
import { capitalize } from './utils';
// in schema/utils.js
export const capitalize = (s) => s.charAt(0).toUpperCase() + s.slice(1);

Did you find this page useful?