[question] Tried to use templateContent too early via TemplateContentPrematureUseError

[nichoth]

Operating system

Mac OS Sequoia 15.5

Eleventy

3.1.0

Describe the bug

Try to add JS data to the window object in a template file, get an error when building.

What does the error mean? How do I avoid this?

Template:

    <script>
        window.__DATA__ = {{ pagination | expose }}
    </script>

eleventy.config.js

export default async function (config) {
    /**
     * Throws the "tried to use template data too soon" error
     */
    config.addFilter('expose', (data) => {
        return `<script>
            window.__DATA__ = JSON.parse('${stringify(data)}');
        </script>`
    })
  // ...

npx @11ty/eleventy

npx @11ty/eleventy

[11ty] Problem writing Eleventy templates:
[11ty] 1. Having trouble rendering njk template ./src/product/index.njk (via TemplateContentRenderError)
[11ty] 2. (./src/product/index.njk) [Line 8, Column 3]
[11ty]   EleventyNunjucksError: Error in Nunjucks Filter `expose` (./src/product/index.njk) (via Template render error)
[11ty] 3. Tried to use templateContent too early on ./src/product/index.njk (via TemplateContentPrematureUseError)
[11ty] Wrote 0 files in 1.07 seconds (v3.1.0)
[11ty] Eleventy Fatal Error (CLI):
[11ty] 1. Having trouble rendering njk template ./src/product/index.njk (via TemplateContentRenderError)
[11ty] 2. (./src/product/index.njk) [Line 8, Column 3]
[11ty]   EleventyNunjucksError: Error in Nunjucks Filter `expose` (./src/product/index.njk) (via Template render error)
[11ty] 3. Tried to use templateContent too early on ./src/product/index.njk (via TemplateContentPrematureUseError)

Reproduction steps

Add a filter that attaches data to the window.

Expected behavior

Build without error

Reproduction URL

No response

Screenshots

[zachleat]

I think you’ll find the information at #3744, we have some internal checks on the content and templateContent properties to help with rendering order.