Allow passing arbitrary JavaScript objects as context, or introduce a separate hash for contextual data

Basic example:

const fs = require('fs')
liquidjs.parseAndRender(layoutContent, {key: 'val', __fs: fs}) // option 1 - part of regular context
liquidjs.parseAndRender(layoutContent, {key: 'val'}, {fs}) // option 2 - third parameter for context data not exposed as {{ variables }}, accessible programatically in tags/filters only

Currently: Error: Cannot convert object to primitive value

Reasoning: I’d like to pass some contextual data to every parseAndRender call that I would access in tag/filter handlers.

Sophisticated example in Gatsby:

  engine.registerTag('asset', {
    // ...
    render: async function (context, emitter, scope, jsContext) { // jsContext, if option 2 is picked
      const assetNode = {
        children: [],
        id: gatsbyApi.createNodeId(`asset-${this.input}`),
        internal: {
          type: 'JekyllAsset',
          contentDigest: gatsbyApi.createContentDigest(this.input),
        },
        outputPath: this.output,
        originalPath: this.originalPath,
      }

      actions.createNode(assetNode)
      actions.createParentChildLink({
        parent: context.getAll().__node, // or jsContext, if option 2 is picked
        child: assetNode
      })
    }
  }

// Then use it in createPages hook:
liquidjs.parseAndRender(template, {page, site, node})

This allows me to perform sophisticated actions inside tags/filters - not just to return a value.

[Nowaker]

Ah, sorry, I forgot to close this. Yeah, it came from somewhere else, not from Liquidjs.

[harttle]

After digging into this a bit, I find the “cannot convert object to primitive value” happens when implicitly converting objects without toString method to string. Like

Object.create(null) + '' 

I checked the codebase and didn’t find similiar expressions. I tried the following code which didn’t throw such an error:

const fs = require('fs')
const { Liquid } = require('.')
const engine = new Liquid();

// [object Object]
console.log(engine.parseAndRenderSync('{{fs}}', {fs}))
// [object Object]foo
console.log(engine.parseAndRenderSync('{{fs | append: "foo"}}', {fs}))

Closing this issue since LiquidJS actually allows arbitrary JavaScript objects as contexts. Feel free to open another issue with a runnable snippet if somewhere in LiquidJS throws “Error: Cannot convert object to primitive value”.