Interface IFormatter

Optionalfilters

format

• format(value: any): string

  Formats any value, according to its type.

  Parameters

  • value: any

  Returns string

  Formatted string.

  Example

  import {IFormatter} from 'custom-string-formatter';
  
  class BaseFormatter implements IFormatter {
      format(value: any): string {
          // your own value formatting here;
          return (value ?? 'null').toString();
      }
  }
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OptionalgetDefaultFilter

• getDefaultFilter(filter: string, args: string[]): undefined | IFilter<any, any>

  Optional override for when a filter cannot be found, to provide an alternative filter. When no alternative can be provided, the function should return undefined / null, for the parser to default to throwing an error.

  Usage Scenarios:

  • Support for filter aliases when multiple filter names must be resolved into one filter.
  • Support for dynamic filters. For example, to lazy-load filters and add them to the list upon first use.

  Parameters

  • filter: string

    Filter Name.
  • args: string[]

    Raw filter arguments (not decoded).

  Returns undefined | IFilter<any, any>

  An alternative filter, or nothing (if no alternative filter can be provided).

  Example

  // Example of aliasing a filter name to an existing filter;
  
  import {IFormatter} from 'custom-string-formatter';
  
  class BaseFormatter implements IFormatter {
      getDefaultFilter(filter: string, args: string[]): IFilter | undefined {
          if (filter === 'object' || filter === 'any') {
              return this.filters.json; // alias to another filter
          }
          // else nothing, to throw default error
      }
  
      filters = {
          json: new JsonFilter()
      }
  }
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OptionalgetDefaultValue

• getDefaultValue(prop: string, params: { [key: string]: any }): any

  Optional override to produce a default value whenever the target property does not exist. This will prevent throwing an error, which is not the safest approach.

  Parameters

  • prop: string

    Name of the property that failed to resolve the value (it does not exist).
  • params: { [key: string]: any }

    Parameter object that the property was being resolved against.

  Returns any

  Default value to be used whenever a property fails to be resolved.

  Example

  import {IFormatter} from 'custom-string-formatter';
  
  class BaseFormatter implements IFormatter {
      getDefaultValue(prop: string, params: { [key: string]: any }) {
          // return whatever is to be the default for properties,
          // including nothing (undefined)
      }
  }
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