## 📖 API short reference (incomplete) & available series

### 1. `queryCPI(start, end, { frequency, series })`

| Parameter   | Type / Allowed values                    | Default   | Description                                                   |
|-------------|-------------------------------------------|-----------|---------------------------------------------------------------|
| `start`     | `string` (`YYYY` **or** `YYYY-MM`)       | —         | First observation (inclusive)                                 |
| `end`       | `string` (`YYYY` **or** `YYYY-MM`)       | —         | Last observation (inclusive)                                  |
| `frequency` | `'monthly'` \| `'yearly'`                | `'monthly'` | Return monthly or yearly rows                                 |
| `series`    | `string[]`                               | `[]`      | Which CPI columns to include & parse as `number` in the result |

> Returns `Array<{ date: string, [seriesKey]: number|null }>`  
> Cells without an official observation are returned as `null`.

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### 2. `convertPrice(price, priceDate, { seriesKey, frequency, baseDate })`

| Option       | Default      | Meaning                                                                                  |
|--------------|--------------|------------------------------------------------------------------------------------------|
| `seriesKey`  | `'index'`    | Column to use for deflation (any key listed below)                                       |
| `frequency`  | `'monthly'`  | CPI granularity that matches `priceDate`                                                 |
| `baseDate`   | *latest obs* | Reference date whose CPI becomes **100 %** in the output value                           |

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### 3. `convertPrices(priceRows, { seriesKey, frequency, baseDate })`

Vectorised version of `convertPrice`.  
Each object in `priceRows` must contain `{ date: string, price: number }`.  
The function appends two fields:

| Field | Meaning                                 |
|-------|-----------------------------------------|
| `cpi` | CPI value used for that row             |
| `real`| Price expressed in “`baseDate` euros”   |

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### 4. CPI **series keys**

Below is the complete column set shipped with **v1.0.4** – pass any of them to
`series` (array) or `seriesKey` (single-value) options.  
Numbers shown are *example* values from a single recent monthly row; `"None"` means the column exists but did **not** yet have an observation for that date.

| Key       | Example value | Description (Statistik-Austria shorthand)                        |
|-----------|--------------:|------------------------------------------------------------------|
| `vpi_2020`| `"None"`      | **VPI** (base year 2020 = 100)                                   |
| `vpi_2015`| `"None"`      | VPI (base 2015)                                                  |
| `vpi_2010`| `"None"`      | VPI (base 2010)                                                  |
| `vpi_2005`| `"None"`      | VPI (base 2005)                                                  |
| `vpi_2000`| `"None"`      | VPI (base 2000)                                                  |
| `vpi_96`  | `"None"`      | VPI (base 1996)                                                  |
| `vpi_86`  | **113.1**     | VPI (base 1986)                                                  |
| `vpi_76`  | **175.9**     | VPI (base 1976)                                                  |
| `vpi_66`  | **308.6**     | VPI (base 1966)                                                  |
| `vpi_i`   | **393.2**     | VPI index I (“Inländerkonzept”)                                  |
| `vpi_ii`  | **394.5**     | VPI index II (“Gebietskonzept”)                                  |
| `khpi`    | **2977.9**    | **KHPI**  (harmonised index of consumer prices, EU methodology)  |
| `lhki_45` | **3455.3**    | **LHKI** weighting pattern 45 % (large households, housing cost) |
| `lhki_38` | **2934.8**    | LHKI weighting pattern 38 %                                      |
| `index`   | —            | Alias to the current headline VPI base (usually `vpi_2020`)       |

> **Tip:** call `queryCPI("2020-01","2020-01")` without a `series` array to inspect *all* columns and confirm the current base alias.

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*The series list is updated whenever **Statistik Austria** revises or rebases the CPI.  Use `getLatestValue("vpi_2020")` to programmatically discover new keys at runtime.*