swc_ecma_minifier 61.0.7

EcmaScript code minifier.
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use swc_ecma_ast::*;
use swc_ecma_utils::ExprExt;

use super::Optimizer;

impl Optimizer<'_> {
    /// Drop arguments of `Symbol()` call.
    pub(super) fn drop_arguments_of_symbol_call(&mut self, e: &mut CallExpr) {
        if !self.options.unsafe_symbols {
            return;
        }

        match &e.callee {
            Callee::Super(_) | Callee::Import(_) => return,
            Callee::Expr(callee) => match &**callee {
                Expr::Ident(Ident { sym, ctxt, .. })
                    if &**sym == "Symbol" && *ctxt == self.ctx.expr_ctx.unresolved_ctxt => {}
                _ => return,
            },
            #[cfg(swc_ast_unknown)]
            _ => panic!("unable to access unknown nodes"),
        }

        let preserve_first_arg = e
            .args
            .iter()
            .position(|arg| arg.spread.is_none())
            .filter(|&index| e.args[index + 1..].iter().any(|arg| arg.spread.is_some()));
        let mut index = 0;
        e.args.retain(|arg| {
            let should_retain = (Some(index) == preserve_first_arg)
                || arg.spread.is_some()
                || arg.expr.may_have_side_effects(self.ctx.expr_ctx);
            index += 1;
            should_retain
        });
    }
}