simple_mapper

Description:

simple mapper

Maps objects of different types to other objects using configured expressions.
The goal of this library is to simplify and reduce code needed to map objects.
Usage #
Simple 1-to-1 mapping #
Map configurations can be added by passing a callback that takes the source
object and calling mapper as arguments and returns the destination object.
var mapper = Mapper()
.addMap<CompanyB, CompanyA>((source, mapper) => CompanyB(
id: source.id,
name: source.name,
));

var companyA = CompanyA(
id: 1,
name: 'ABC',
);

var companyB = mapper.map<CompanyB, CompanyA>(companyA);
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Mapping children #
The mapper can be used in the callback to map children.
var mapper = Mapper()
.addMap<CompanyB, CompanyA>((source, mapper, [params]) => CompanyB(
id: source.id,
name: source.name,
employees: source.employees
?.map((employee) => mapper.map<EmployeeB, EmployeeA>(employee))
?.toList(),
))
.addMap<EmployeeB, EmployeeA>((source, mapper, [params]) => EmployeeB(
id: source.id,
name: source.name,
startDate: source.startDate,
timeEmployed: source.startDate == null || source.endDate == null ?
null :
source.endDate.difference(source.startDate),
company: mapper.map<CompanyB, CompanyA>(source.company),
));
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Mapping null #
The callback is only executed if the source is not null; so null checking in the
expression is unnecessary. When null is passed to the map method, null is
returned.
var company = mapper.map<CompanyB, CompanyA>(null);
print(company == null); // true
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Mapping additional parameters #
In some cases the source may not contain all of the data that you want to map
to the destination. In these cases you can pass additional parameters.
var mapper = Mapper()
.addMap<CompanyB, CompanyA>((source, mapper, [params]) => CompanyB(
id: source.id,
name: source.name,
employees: source.employees
?.map((employee) => mapper.map<EmployeeB, EmployeeA>(employee, {
'companyId': source.id,
}))
?.toList(),
))
.addMap<EmployeeB, EmployeeA>((source, mapper, [params]) => EmployeeB(
id: source.id,
companyId: params != null ? params['companyId'] : null,
name: source.name,
startDate: source.startDate,
timeEmployed: source.startDate == null || source.endDate == null ?
null :
source.endDate.difference(source.startDate),
));
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