finnish.md

Enforce Finnish notation (rxjs-x/finnish)

💭 This rule requires type information.

This rule enforces the use of Finnish notation - i.e. the $ suffix.

Rule details

Examples of incorrect code for this rule:

const answers = of(42, 54);

Examples of correct code for this rule:

const answer$ = of(42, 54);

Options

Name	Description	Type
functions	Require for functions.	Boolean
methods	Require for methods.	Boolean
names	Enforce for specific names. Keys are a RegExp, values are a boolean.	Object
parameters	Require for parameters.	Boolean
properties	Require for properties.	Boolean
strict	Disallow Finnish notation for non-Observables.	Boolean
types	Enforce for specific types. Keys are a RegExp, values are a boolean.	Object
variables	Require for variables.	Boolean

This rule accepts a single option which is an object with properties that determine whether Finnish notation is enforced for functions, methods, parameters, properties and variables. It also contains:

• names and types properties that determine whether or not Finnish notation is to be enforced for specific names or types.
• a strict property that, if true, allows the $ suffix to be used only with identifiers that have an Observable type.

The default (Angular-friendly) configuration looks like this:

{
    "rxjs-x/finnish": [
        "error",
        {
            "functions": true,
            "methods": true,
            "names": {
                "^(canActivate|canActivateChild|canDeactivate|canLoad|intercept|resolve|validate)$": false
            },
            "parameters": true,
            "properties": true,
            "strict": false,
            "types": {
                "^EventEmitter$": false
            },
            "variables": true
        }
    ]
}

The properties in the options object are themselves optional; they do not all have to be specified.

When Not To Use It

If you don't use Finnish notation in your project or don't care about enforcing Finnish notation in your project, you don't need this rule. However, keep in mind that inconsistent style can harm readability in a project; consider using no-finnish to ban Finnish notation if you don't use it in your project.

Type checked lint rules are more powerful than traditional lint rules, but also require configuring type checked linting.

Further reading

• Observables and Finnish Notation

Related To

• no-finnish
• suffix-subjects

Resources

• Rule source
• Test source