mapper-ts

A convention-based object mapper that utilizes TypeScript decorators to simplify the mapping of objects between themselves.

Usage

Importing modules

// importing modules
import { Mapper, AddMap, IgnoreMap } from 'mapper-ts';

Update tsconfig.json to enable decorators, if not already enabled.

{
  "compilerOptions": {
    "experimentalDecorators": true,
    // ...
  }
}

Examples

Mapping properties in a class

class AClass {
  // Mapping a property by name
  @AddMap('prop1B')
  prop1A: string;
  @AddMap('prop2B')
  prop2A: number;

  constructor(prop1A: string, prop2A: number) {
    this.prop1A = prop1A;
    this.prop2A = prop2A;
  }
}

class BClass {
  @AddMap('prop1A')
  prop1B: string;
  @AddMap('prop2A')
  prop2B: number;

  // Any properties that don't need to be mapped simply shouldn't have the @AddMap() decorator.
  unmappedProp1B: number;
  unmappedProp2B: string;

  // Mapping an object property by passing it's type
  @AddMap(AClass)
  propAClass: AClass;
}

// Any property name in @IgnoreMap() will be ignored from the source object if it exists in it
@IgnoreMap('ignoredObj', 'ignoredProp', 'nonexistantProp')
class CClass {
  @AddMap('prop1A')
  prop1C: string;
  @AddMap('prop2A')
  prop2C: number;

  // Also valid if an object's property name also needs to be mapped
  @AddMap(BClass, 'anyPropName')
  propBClass: BClass;
}

Calling the Mapper.map() method

const unmappedA = { prop1B: 'PROP 1B', prop2B: 10 };

const unmappedB = {
  prop1A: 'PROP 1B',
  prop2A: 10,
  unmappedProp1B: 20,
  unmappedProp2B: 'UNMAPPED 2B',
  propAClass:  { prop1B: 'PROP 1B in A', prop2B: 300 };
};

const unmappedC = {
  prop1A: 'PROP 1A',
  prop2A: 20,
  anyPropName: {
    prop1A: 'PROP 1A in C',
    prop2A: 20,
    unmappedProp1B: 20,
    unmappedProp2B: 'UNMAPPED 2B in C',
  },
  ignoredObj: {
    ignoredProp1: 'IGNORED PROP in obj',
    ignoredProp2: 'IGNORED PROP in obj2',
  },
  ignoredProp: 'IGNORED PROP',
};


const mappedA = new Mapper(AClass).map(unmappedA);

const mappedB = new Mapper(BClass).map(unmappedB);

const mappedC = new Mapper(CClass).map(unmappedC);

# Results:
AClass { prop1A: 'PROP 1B', prop2A: 10 }
BClass {
  prop1B: 'PROP 1B',
  prop2B: 10,
  unmappedProp1B: 20,
  unmappedProp2B: 'UNMAPPED 2B',
  propAClass: AClass { prop1A: 'PROP 1B in A', prop2A: 300 }
}
CClass {
  prop1C: 'PROP 1A',
  prop2C: 20,
  propBClass: BClass {
    prop1B: 'PROP 1A in C',
    prop2B: 20,
    unmappedProp1B: 20,
    unmappedProp2B: 'UNMAPPED 2B in C',
    propAClass: null
  }
}

Compiling the source code to JS files

• To compile all the code in the src folder to the lib-esm folder, run this command at the root of the project with typescript installed:

tsc

• All configuration for this command is already set in tsconfig.json