@toreda/strong-types
Native TypeScript containers for generic value storage. Reliably store and retrieve typed values without writing validation or type checking code. Use built-in types or define your own.
What does it do?
import {StrongInt, makeInt} from '@toreda/strong-types';
// int with initial value 10.
const int = makeInt(10, 0);
// Prints 10. It always return an int.
console.log(int());
// Set the value
int(11);
// Prints 11.
console.log(int());
// Won't set the value - it's not an int.
int(null);
int(undefined);
int(3.33);
int({});
// Prints 11
console.log(int());
Contents
StrongType
Using Each built-in type exports a type and make function. The below examples use StrongInt but work the same using: StrongArray
, StrongBoolean
, StrongDouble
, StrongInt
, StrongString
, and StrongUInt
.
Instantiate with initial value
import {StrongInt, makeInt} from '@toreda/strong-types';
const initial = 11;
const fallback = 55;
const int = makeInt(initial, fallback);
// Returns 11 - initial value was 11.
const value = int();
Instantiate without initial value
import {StrongInt, makeInt} from '@toreda/strong-types';
const fallback = 919;
const int = makeInt(null, fallback);
// value is 919 - initial value was null, so fallback was
// returned instead to maintain the function's return type guarantee.
const value = int();
Get with Fallback
get(fallback: T): T
Callcontainer.get(fallback)
when a per-call fallback is preferred instead of the container's default fallback.
import {StrongInt, makeInt} from '@toreda/strong-types';
const int = makeInt(null, 555);
const fallback = 331;
// Prints 331 (fallback) instead of 555 (container default fallback).
console.log(value.get(fallback));
GetNull
getNull(): T | null
Callcontainer.getNull()
to the current value, even if null. Value will never be undefined and will always return either null, or a value of container's generic type T.
NOTE: getNull
DOES NOT take a fallback argument and will not return the container's default fallback. It always returns value (null
or StrongType<T>
).
import {StrongInt, makeInt} from '@toreda/strong-types';
const fallback = 919;
const int = makeInt(null, fallback);
// Prints null. Default fallback is not used for `getNull` calls.
console.log(int.getNull());
Set Value
import {StrongInt, makeInt} from '@toreda/strong-types';
const initial = 331;
const fallback = 400;
const int = makeInt(initial, fallback);
// value is 331 - the int's initial value.
const value = int();
// Set int to a new value.
int(555);
// value is 555 - the value we updated int to.
const value = int();
null
Set import {StrongInt, makeInt} from '@toreda/strong-types';
const initial = 414;
const fallback = 500;
const int = makeInt(initial, fallback);
// value is 414 - the int's initial value.
const value = int();
// Set value to null.
int(null);
// value is 500 - Fallback returned because value was null.
const value = int();
Reset Value
Call myContainer.reset()
to reset value without creating a new StrongType container. Default Fallback will not be reset. Useful for unit testing and serverless environments where the previous container value or state is unknown.
import {StrongInt, makeInt} from '@toreda/strong-types';
const initial = 515;
const fallback = 600;
const int = makeInt(initial, fallback);
// value is 515 (the initial value).
const value = int();
// Reset container value
int.reset();
// Prints 600 (fallback). value was reset to null,
// fallback was returned to maintain return type guarantee.
console.log(int());
Validation
StrongType
containers validate value inputs before setting. Bad values are ignored and will not cause a throw. Each built-in container type provides specific guarantees for which values are allowed.
import {StrongInt, makeInt} from '@toreda/strong-types';
const int = makeInt(50, 100);
// success is false.
// container.value is still it's initial value 50 because 1.5 is not an int.
// StrongInt does not round or truncate non-integers. They are simply ignored.
const success = int(1.5);
Supported Types
StrongArray
, arraysStrongBoolean
, booleans (strict)StrongDouble
, doublesStrongInt
, integersStrongUInt
, unsigned integersStrongString
- strings
StrongMap
Using Creating and using a StrongMap class.
import {StrongMap, StrongInt, StrongString, makeInt, makeString} from '@toreda/strong-types';
export class SomeConfig extends StrongMap {
public readonly counter: StrongInt;
public readonly name: StrongString;
constructor(json: any) {
super();
this.counter = makeInt(0, 0);
this.name = makeString(null, 'TreeBeard');
this.parse(json);
}
}
// Use it
const myConfig = new SomeConfig();
// Prints '0'
console.log(myConfig.counter());
// Prints 'Treebeard'
console.log(myConfig.name());
Creating a StrongMap
and loading values from JSON
import {StrongMap, StringInt, StrongString, makeInt, makeString} from '@toreda/strong-types';
export class SomeConfig extends StrongMap {
public readonly counter: StrongInt;
public readonly name: StrongString;
constructor(json?: any) {
super();
this.counter = makeInt(0, 0);
this.name = makeString(null, 'TreeBeard');
this.parse(json);
}
}
const myJSON = {
'counter': 99,
'name': 'Sauron'
};
// Load the recursively parse a JSON object.
const myConfig = new SomeConfig(myJSON);
// Prints 99 - myJSON.counter was loaded into SomeConfig.counter at instantiation.
console.log(myConfig.counter());
// Prints 'Sauron' - myJSON.name was loaded into SomeConfig.name at instantiation.
console.log(myConfig.name());
Converting a StrongMap
to a json object
import {StrongMap, StringInt, StrongString, makeInt, makeString} from '@toreda/strong-types';
export class SomeConfig extends StrongMap {
public readonly counter: StrongInt;
public readonly name: StrongString;
constructor(json?: any) {
super();
this.counter = makeInt(0, 0);
this.name = makeString(null, 'TreeBeard');
this.parse(json);
}
}
const myJSON = {
'counter': 99,
'name': 'Sauron'
};
// Create the StrongMap with myJSON data
const myConfig = new SomeConfig(myJSON);
// Change a value in the StrongMap
myConfig.name('Gandalf');
// {counter: 99, name: 'Gandalf'}
const configAsJSON = myConfig.jsonify();
StrongArray
Import
import {StrongArray, makeArray} from '@toreda/strong-types';
Accepted Values
- Arrays holding any type (e.g.
T[]
) - Accepts empty arrays (e.g.
[]
)
StrongBoolean
Import
import {StrongBoolean, makeBoolean} from '@toreda/strong-types';
Accepted Values
- Strict booleans:
true
orfalse
only. - No type coercion (e.g.
1
or0
will be rejected).
StrongDouble
Import
import {StrongDouble, makeDouble} from '@toreda/strong-types';
Accepted Values
number
values between and including Number.MIN_VALUE and Number.MAX_VALUE.- Rejects
NaN
values.
StrongInt
Import
import {StrongInt, makeInt} from '@toreda/strong-types';
Accepted Values
number
values between and including Number.MIN_VALUE and Number.MAX_VALUE.NaN
values are rejected.
StrongString
Import
import {StrongString, makeString} from '@toreda/strong-types';
Accepted Values
string
values of any valid length.
StrongUInt
Import
import {StrongUInt, makeUInt} from '@toreda/strong-types';
Accepted Values
- Integers between and including 0 and
Number.MAX_SAFE_INTEGER
. - Rejects numbers which are non-integers (e.g.
1.5
) - Rejects
NaN
- Rejected negative integers (e.g.
-22
).
Custom Types
Each built-in type like StrongInt
and StrongUInt
are helper functions wrapping StrongType<T>
. They also apply validators which guarantee the StrongType<T>
value behaves as expected. While built-ins are provided for convenience, you can create custom types with your own validators.
StrongType<T>
Instantiate import {StrongType, makeStrong} from '@toreda/strong-types';
export type MyOwnType = {
id: string | null;
name: string | null;
};
const initial: MyOwnType = {
id: 'hello',
name: 'my name is'
};
const fallback: MyOwnType = {
id: null,
name: null
};
const myObj = makeStrong<MyOwnType>(initial, fallback);
Validators
Install
Install @toreda/strong-types
directly from NPM or clone the Github repo.
Install using Yarn (preferred)
- Open a shell (or console).
- Navigate to the the StrongTypes root project folder.
- Enter the following commands in order. Wait for each to complete before typing the next.
yarn
Install using NPM
- Open a shell (or console).
- Navigate to the the StrongTypes root project folder.
- Enter the following commands in order. Wait for each to complete before typing the next.
npm install
Run Unit Tests
Install or clone StrongTypes (see above).
StrongTypes tests are written with Jest which is also a project dev dependency.
Installing jest is not required after project dependencies are installed (see above).
yarn test
Build from source
The next steps are the same whether you installed the package using NPM or cloned the repo from Github.
Build with Yarn
Enter the following commands in order from the StrongTypes root project folder.
yarn build
Build with NPM
Enter the following commands in order from the StrongTypes root project folder.
npm run-script build
License
MIT © Toreda, Inc.