@alicloud/typescript-missing-helpers

Supplements to TypeScript type helpers.

``typescript
import {
PartialPick,
RequiredPick,
PartialSelected,
RequiredSelected,
PartialUnselected,
RequiredUnselected,
PartialBut,
RequiredBut
} from '@alicloud/typescript-missing-helpers';
`

PartialPick

Pick properties defined by K from T make them optional.

`typescript
interface Original {
a?: string;
b: number;
c: boolean;
d?: Date;
}

// Alt === {
// a?: string;
// b?: number;
// }
type Alt = PartialPick;

// OK
const o1: Alt = { a: '', b: 1 };
const o2: Alt = { a: '' };
const o3: Alt = { b: 1 };
const o4: Alt = {};
// Error: Object literal may only specify known properties...
const o5: Alt = { c: true };
const o6: Alt = { d: new Date };
`

RequiredPick

Pick properties defined by K from T make them required.

`typescript
interface Original {
a?: string;
b: number;
c: boolean;
d?: Date;
}

// Alt === {
// a: string;
// b: number;
// }
type Alt = RequiredPick;

// OK
const o1: Alt = { a: '', b: 1 };
// Error
const o2: Alt = { a: '' }; // missing b
const o3: Alt = { b: 1 }; // missing a
const o4: Alt = {}; // missing a, b
const o5: Alt = { a: '', b: 1, c: true }; // unknown property c
`

PartialSelected

Make properties defined by K in T optional, the rest untouched.

`typescript
interface Original {
a?: string;
b: number;
c: boolean;
d?: Date;
}

// Alt === {
// a?: string;
// b?: number;
// c: boolean;
// d?: Date;
// }
type Alt = PartialSelected;

// OK
const o1: Alt = { c: true, d: new Date() };
const o2: Alt = { b: 1, c: true, d: new Date() };
const o3: Alt = { a: '', b: 1, c: true, d: new Date() };
const o4: Alt = { c: true };
// Error
const o5: Alt = { b: 1, d: new Date() }; // missing c
const o6: Alt = { a: '', b: 1 }; // missing c
const o7: Alt = { a: '', b: 1, c: true, d: new Date(), e: null }; // e does not exist
`

RequiredSelected

Make properties defined by K in T required, the rest untouched.

`typescript
interface Original {
a?: string;
b: number;
c: boolean;
d?: Date;
}

// Alt === {
// a: string;
// b: number;
// c: boolean;
// d?: Date;
// }
type Alt = RequiredSelected;

// OK
const o1: Alt = { a: '', b: 1, c: false };
const o2: Alt = { a: '', b: 1, c: true, d: new Date() };
// Error
const o3: Alt = { b: 1, c: true, d: new Date() }; // missing a
const o4: Alt = { a: '', b: 1, d: new Date() }; // missing c
const o5: Alt = { a: '', b: 1, c: false, e: null }; // unknown e
`

PartialUnselected

Properties defined by K in T untouched, the rest made optional.

`typescript
interface Original {
a?: string;
b: number;
c: boolean;
d?: Date;
}

// Alt === {
// a?: string;
// b: number;
// c?: boolean;
// d?: Date;
// }
type Alt = PartialUnselected;

// OK
const o1: Alt = { b: 1 };
const o2: Alt = { a: '', b: 1, c: false };
// Error
const o3: Alt = { a: '', c: false }; // missing b
`

RequiredUnselected

Properties defined by K in T untouched, the rest made required.

`typescript
interface Original {
a?: string;
b: number;
c: boolean;
d?: Date;
}

// Alt === {
// a?: string;
// b: number;
// c: boolean;
// d: Date;
// }
type Alt = RequiredUnselected;

// OK
const o1: Alt = { a: '', b: 1, c: false, d: new Date() };
const o2: Alt = { b: 1, c: false, d: new Date() };
// Error
const o3: Alt = { }; // missing b, c, d
const o4: Alt = { a: '' }; // missing b, c, d
const o5: Alt = { a: '', b: 1 }; // missing c, d
const o6: Alt = { a: '', b: 1, c: false }; // missing d
`

PartialBut

Properties defined by K in T required, the rest made optional.

`typescript
interface Original {
a?: string;
b: number;
c: boolean;
d?: Date;
}

// Alt === {
// a: string;
// b: number;
// c?: boolean;
// d?: Date;
// }
type Alt = PartialBut;

// OK
const o1: Alt = { a: '', b: 1 }; // missing c, d
const o2: Alt = { a: '', b: 1, c: false }; // missing d
const o3: Alt = { a: '', b: 1, d: new Date() }; // missing c
const o4: Alt = { a: '', b: 1, c: false, d: new Date() };
// Error
const o5: Alt = { b: 1, c: false, d: new Date() }; // missing a
const o6: Alt = { c: false, d: new Date() }; // missing a, b
const o7: Alt = { a: '' }; // missing b
const o8: Alt = { }; // missing a, b
`

RequiredBut

Properties defined by K in T optional, the rest made required.

`typescript
interface Original {
a?: string;
b: number;
c: boolean;
d?: Date;
}

// Alt === {
// a?: string;
// b?: number;
// c: boolean;
// d: Date;
// }
type Alt = RequiredBut;

// OK
const o1: Alt = { a: '', b: 1, c: false, d: new Date() };
const o2: Alt = { b: 1, c: false, d: new Date() };
const o3: Alt = { c: false, d: new Date() };
// Error
const o4: Alt = { }; // missing c, d
const o5: Alt = { a: '' }; // missing c, d
const o6: Alt = { a: '', b: 1 }; // missing c, d
const o7: Alt = { a: '', b: 1, c: false }; // missing d
const o8: Alt = { a: '', b: 1, d: new Date() }; // missing c
``