How to create a Vec with data type ExprOrSpread for an SWC plugin?

Question

I am developing an SWC plugin in Rust.

[dependencies]
swc_core = "0.75.*"
swc_ecma_parser = "0.133.8"

I need to replace the argument in console.log("hello") with console.log("world")

fn visit_mut_call_expr(&mut self, n: &mut CallExpr) {
    n.args = "new argument";
}

n.args accepts a Vec vector with data type ExprOrSpread.

I don't understand what ExprOrSpread is. Any value returns an error.

It works like this:

fn visit_mut_call_expr(&mut self, n: &mut CallExpr) {
    let mut vector: Vec<ExprOrSpread> = vec![];
    n.args = vector;
}

I replace console.log("hello") with console.log().

How do I insert the string "world"?

Answer 1

In most cases, you're interested in traits such as From<Expr>, which allow you to transform things into each other. And builders or factories to create a new one.

use swc_ecma_ast::*;
use swc_ecma_utils::ExprFactory;

fn visit_mut_call_expr(&mut self, n: &mut CallExpr) {
    let first = Lit::Str("world".into());
    n.args = vec![first.as_arg()];
}