horiuchi / dtsgenerator / 391

91%

Pull #239

travis-ci

feat: minItems, maxItems for array tuples

Using `any` and `Object`, allow enforcement of min- and maxItems in tuples.

E.g.,
```javascript
    array: {
        type: 'array',
        maxItems: 2,
        items: [
            { type: 'string' },
            { type: 'integer' },
            { type: 'boolean' },
        ],
    },
```
yields
```typescript
  [] | [string] | [string, number]
```
and
```javascript
{
    array: {
        type: 'array',
        minItems: 3,
        items: [
            { type: 'string' },
            { type: 'integer' },
            { type: 'boolean' },
        ],
    },
}
```
yields
```typescript
    array?: [string, number, boolean] | [string, number, boolean, any]
```
and
```javascript
    array: {
        type: 'array',
        minItems: 4,
        items: [
            { type: 'string' },
            { type: 'integer' },
            { type: 'boolean' },
        ],
    },
```
yields
```typescript
    [string, number, boolean, Object] | [string, number, boolean, Object, any]
```
and
```javascript
    array: {
        type: 'array',
        minItems: 2,
        maxItems: 4,
        items: [
            { type: 'string' },
            { type: 'integer' },
            { type: 'boolean' },
            { type: 'string' },
            { type: 'integer' },
            { type: 'boolean' },
        ],
    },
```
yields
```typescript
    [string, number] | [string, number, boolean] | [string, number, boolean, string]
```

If `minItems` is greater than `maxItems`, you may have complaints from other tools,
but just to add to them, the generator in such case will render the type:
```typescript
  never
```

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