1 files changed, 80 insertions, 0 deletions
diff --git a/toolkit/components/uniffi-bindgen-gecko-js/src/templates/js/Error.sys.mjs b/toolkit/components/uniffi-bindgen-gecko-js/src/templates/js/Error.sys.mjs
new file mode 100644
index 0000000000..97b1d064d9
--- /dev/null
+++ b/toolkit/components/uniffi-bindgen-gecko-js/src/templates/js/Error.sys.mjs
@@ -0,0 +1,80 @@
+{%- let error = ci.get_error_definition(name).unwrap() %}
+{%- let string_type = Type::String %}
+{%- let string_ffi_converter = string_type.ffi_converter() %}
+
+export class {{ error.nm() }} extends Error {}
+{% for variant in error.variants() %}
+
+export class {{ variant.name().to_upper_camel_case() }} extends {{ error.nm() }} {
+{% if error.is_flat() %}
+    constructor(message, ...params) {
+        super(...params);
+        this.message = message;
+    }
+{%- else %}
+    constructor(
+        {% for field in variant.fields() -%}
+        {{field.nm()}},
+        {% endfor -%}
+        ...params
+    ) {
+        super(...params);
+        {%- for field in variant.fields() %}
+        this.{{field.nm()}} = {{ field.nm() }};
+        {%- endfor %}
+    }
+{%- endif %}
+    toString() {
+        return `{{ variant.name().to_upper_camel_case() }}: ${super.toString()}`
+    }
+}
+{%- endfor %}
+
+// Export the FFIConverter object to make external types work.
+export class {{ ffi_converter }} extends FfiConverterArrayBuffer {
+    static read(dataStream) {
+        switch (dataStream.readInt32()) {
+            {%- for variant in error.variants() %}
+            case {{ loop.index }}:
+                {%- if error.is_flat() %}
+                return new {{ variant.name().to_upper_camel_case()  }}({{ string_ffi_converter }}.read(dataStream));
+                {%- else %}
+                return new {{ variant.name().to_upper_camel_case()  }}(
+                    {%- for field in variant.fields() %}
+                    {{ field.ffi_converter() }}.read(dataStream){%- if loop.last %}{% else %}, {%- endif %}
+                    {%- endfor %}
+                    );
+                {%- endif %}
+            {%- endfor %}
+            default:
+                throw new Error("Unknown {{ error.nm() }} variant");
+        }
+    }
+    static computeSize(value) {
+        // Size of the Int indicating the variant
+        let totalSize = 4;
+        {%- for variant in error.variants() %}
+        if (value instanceof {{ variant.name().to_upper_camel_case() }}) {
+            {%- for field in variant.fields() %}
+            totalSize += {{ field.ffi_converter() }}.computeSize(value.{{ field.nm() }});
+            {%- endfor %}
+            return totalSize;
+        }
+        {%- endfor %}
+        throw new Error("Unknown {{ error.nm() }} variant");
+    }
+    static write(dataStream, value) {
+        {%- for variant in error.variants() %}
+        if (value instanceof {{ variant.name().to_upper_camel_case() }}) {
+            dataStream.writeInt32({{ loop.index }});
+            {%- for field in variant.fields() %}
+            {{ field.ffi_converter() }}.write(dataStream, value.{{ field.nm() }});
+            {%- endfor %}
+            return;
+        }
+        {%- endfor %}
+        throw new Error("Unknown {{ error.nm() }} variant");
+    }
+
+    static errorClass = {{ error.nm() }};
+}