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Field Logging

Joist provides field logging to visualize when/why fields are being set on entities.

Usage​

Field logging is currently enabled on an individual EntityManager instance:

import { FieldLogger} from "joist-orm";
// This will log any field set field sets on this EntityManager
em.setFieldLogging(new FieldLogger());

This will produce output like:

a#1.firstName = a1 at newAuthor.ts:13
a#1.age = 40 at newAuthor.ts:13
b#1.title = title at newBook.ts:9
b#1.order = 1 at newBook.ts:9
b#1.author = Author#1 at newBook.ts:9
b#1.notes = Notes for title at defaults.ts:28

Where a#1 is the tagged id of a new/unsaved Author instance, and b# is the tagged if of a new/unsaved Book instance.

The at (file):(line), which should help track down which hook or method is setting the field.

info

The code that determines the correct at (file):(line) to output is currently a heuristic; if you see incorrect or missing file/line information, please file an issue. Thank you!

Filtering by Entity​

If you want to log only sets for a specific entity type, you can pass a watches argument to the FieldLogger constructor:

em.setFieldLogging(new FieldLogger(
  [{ entity: "Author" }],
));

Filtering by Entity and Field​

If you want to log only sets for a specific entity and field name, you can pass a watches argument to the FieldLogger constructor:

em.setFieldLogging(new FieldLogger(
  [{ entity: "Author", fieldNames: ["firstName"] }],
));

Enabling Breakpoints​

If you're running code in debug mode, you can also tell Joist to trigger a breakpoint, whenever a field is set:

em.setFieldLogging(new FieldLogger(
  [{ entity: "Author", fieldNames: ["firstName"], breakpoint: true }],
));

Colorized Output​

Currently, the FieldLogger always output colorized output, similar to Joist's other logging output.

This makes for the best experience with running/debugging tests, like in Jest, which is currently the primary use case for Joist's logging.