renderStringAsync not working in Angular 17

[vjm14]

Describe the bug We are trying to use renderStringAsync function to execute a custom function with an await, but we always get an error.

We are using Angular 17.

To Reproduce

const eta = new Eta({
                autoEscape: false,
                tags: ["{{", "}}"],
                varName: 'listOf',
                useWith: true
});

const result = eta.renderStringAsync(`Hello {{= await  hello(test1) }} \n\n {{= await world(test2) }}`, {
          test1: "hello",
          test2: "world",
          hello: (e) => Promise.resolve(e),
          world: (e) => Promise.resolve(e)
})

Error encountered:

Expected behavior Expecting to behave the same in the documentation.

Package & Environment Details

• Environment: Node version 20.10.0
• ETA Version: 3.4.0
• ES build
• Angular CLI: 17.0.10
• Package Manager: npm 10.2.3
• OS: win32 x64

[nebrelbug]

@vjm14 hmm, this is a bit confusing. It's working when I try your code in a clean environment. Could it be something about Angular?

See https://runkit.com/embed/vlwyx6jco93r

[vjm14]

@nebrelbug I appreciate you looking at this. We're simply switching over to ETA from squirrelly at the moment. We can run the async await function in angular without any problems when using squirrelly, but we are unable to do so using ETA.

[vjm14]

@nebrelbug We tried to debug the ETA and this is what we see. Since async is set to true, the "ctor" is being set as a Function, not as a AsyncFunction. Do you have any suggestions or alternatives that i can do?

[vjm14]

@nebrelbug I think we resolve the issue. We tried to copy the AsyncFunction in squirrelly and replace it in ETA and it works. We don't get the error anymore.

ETA:
 const AsyncFunction = async function () {}.constructor; // Not working in Angular

Squirrelly:
const AsyncFunction = new Function('return (async function(){}).constructor')(); // Working in Angular

[nebrelbug]

@vjm14 glad to hear you solved it! I'm guessing it has to do with some perplexity of Angular's execution environment, where async works in one context but not in another. I'll close this as resolved, since I don't think this is a common issue.