Page content must be a list of strings or components
The error
The content of a Page must be a list of strings or components.
Found int instead.
The friendly version: "The content you returned in this Page was an int, but it needs to be text, a component, or a list of those." A related message appears when the list itself is fine but one item inside it is not; that message names the route and the offending item.
What it means
A Page displays a list of strings and components. Something you
put into that list, or in place of the list itself, was neither a
string nor a component: perhaps a number, a dataclass, or a nested
list. Drafter stopped rather than guess how to display it.
Where to look
Start with the route named in the message. Look at the Page(...)
call it returns and read the content list item by item.
Check
- A bare value:
Page(state, state.score)passes a number where the content list belongs. Content must be a list. - A number in the list:
Page(state, ["Score:", state.score]); every non-text value needsstr()around it. - A dataclass in the list:
Page(state, [state.pet]); show its fields (state.pet.name) or use a component like Table built for structured data. - A missing comma: two adjacent strings without a comma merge into one string, which Python allows, but a component next to a string without its comma is a syntax error that would appear before this one.
Fix
Convert values to strings and keep everything inside one flat list:
@route
def index(state: State) -> Page:
return Page(state, [
"Score: " + str(state.score) + "\n",
Button("Play", "play")
])
Confirm
The page renders. A structural test pins it down:
assert_has(index(State(3)), "Score: 3").
Prevent
Get in the habit of wrapping str() around any number or other
value that goes into page content, and keep the content list flat:
helper functions that produce several components should return a
list you add with +, not nest as an item.
Understand
Page documents exactly what content can hold; Routes and pages explains the underlying concept.