Typescript service for Digitronic Dwh interface

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``bash
yarn add dwh-fetch
`

Start coding!

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- fetch DigiWEB variables as strings, or integers or as arrays
- map results of DigiWeb variables to objects using the @Expression decorator

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`typescript
import DwhFetch from 'dwh-fetch'
`

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`typescript
const dwh = new DwhFetch();

// fetch a simple variable to promise
dwh.fetchString('##000187').then(value => console.log(value));

(async () => {
// or with await ...
const value = await dwh.fetchString('##000187');
})();
`

`typescript
const dwh = new DwhFetch();

(async () => {

// fetch as Number to convert the result to number before returning
const aNumber = await dwh.fetchNumber('##000187');
const isNumber = aNumber instanceof Number; // true

})();
`

`typescript
const dwh = new DwhFetch();

(async () => {

// fetch as Number to convert the result to number before returning
const result = await dwh.fetch(['##A', '##B']);
console.log(result.accessRights); //current accessRights from the request
console.log(result.lines[0].success); //boolean indicates that request has been successful processed or not
console.log(result.lines[0].value); //value of ##A or errorCode if success is false
console.log(result.lines[1].success); //boolean indicates that request has been successful processed or not
console.log(result.lines[1].value); //value of ##B or errorCode if success is false

})();
`

It's also possible to map values to objects and convert the results directly

`typescript
interface Test {
timer: number;
firmware: string;
}

const expressions: ExpressionDefinitions = {
timer: Expression.integer('##000187'),
firmware: Expression.string('#$000199')
};
(async () => {
const dwhFetch = new DwhFetch();
const values: Test = await fetchExpressions(dwhFetch, expressions);
console.log(values);
})();

`

This is also possible with array like expressions and using G= requests
`typescript
import {
Expression,
ExpressionDefinitions,
fetchExpressions,
fetchIndexed
} from '../fetch-indexed';
import { DwhFetch } from '../dwh-fetch';

interface Test {
num: number;
str: string;
}

const expressions: ExpressionDefinitions = {
num: Expression.integer('##Module[##X].num'),
str: Expression.string('##Module[##X].str')
};
(async () => {
const dwhFetch = new DwhFetch();
const values: Test[] = await fetchIndexed(dwhFetch, '##Module.Count', expressions);
console.log(values);
})();

`

This is also possible with multiple ExpressionDefinitions in one call
`typescript
//expression store holds all the requests that should be sent in one request
const store = new ExpressionStore();
// add the first expressions. Note that this won't resolve util fetchExpressionStore has been called and awaited
const first = store.add({
a: Expression.string('#$str[$(index)]'),
b: Expression.integer('##num[$(index)]'),
});
// add the first expressions. Note that this won't resolve util fetchExpressionStore has been called and awaited
const second = store.add({
c: Expression.string('#$str'),
d: Expression.integer('##num'),
e: Expression.string('#$str'),
});
// fetch data from dwh
await fetchExpressionStore(dwhFetch, store);
// now the promises from the expressionstore can be awaited
console.log(await first); // { a: 'str', b: 7 }
console.log(await second); // { c: 'str', d: 7, e: 'str' }

``