Quantities in "mg" are returned in "g" from the API. product_quantity type changes based on unit.

[theedov]

What

Few issues:

• 9344962003855: "product_quantity" is 175mg but API returns 0.75 with "g" unit. Also there's an issue with "product_quantity" type, if it's in grams, the type is string("175"), but when it's mg, the type is number(0.75).
• 9310653105610: Also for web it seems that salt is entered in "mg", but is shown in "g". While calcium is entered in "mg" and is correctly shown in "mg".

Expected behavior

If entered in MG, API should return MG value, etc...

Screenshot/Mockup/Before-After

Type of device

REST-API

Number of products impacted

See at least 1.

[stephanegigandet]

Hi @theedov ,

The API converts all entered value in a default unit (g for most nutrients), and stores it in the _100g and _serving fields.
Then the client can convert it to other units as it decides. On the OFF website for instance, in Europe we display salt in grams, while we display it in mg for the US.

The type number / string issue is a long standing issue due to the Perl internals that convert types on the fly, we have not found a solution for that.

Same for product_quantity: it is always converted to g or to ml.

[stephanegigandet]

There's a bit more details in https://github.com/openfoodfacts/openfoodfacts-server/blob/main/docs/api/ref/schemas/product_nutrition.yaml#L147

[theedov]

@stephanegigandet Thank you for the explanation. Quick question, does API always return _100g values or there are scenarios when it's not there?