use maps instead

site/content/docs/03-run-time.md

@@ -904,7 +904,7 @@ The following initialisation options can be provided:
 | `target` | **none** | An `HTMLElement` to render to. This option is required
 | `anchor` | `null` | A child of `target` to render the component immediately before
 | `props` | `{}` | An object of properties to supply to the component
-| `context` | `{}` | An object of context to supply to the component
+| `context` | `new Map()` | A `Map` of context key-value pairs to supply to the component
 | `hydrate` | `false` | See below
 | `intro` | `false` | If `true`, will play transitions on initial render, rather than waiting for subsequent state changes
 

src/runtime/internal/Component.ts

@@ -120,7 +120,7 @@ export function init(component, options, instance, create_fragment, not_equal, p
 		on_disconnect: [],
 		before_update: [],
 		after_update: [],
-		context: new Map(parent_component ? parent_component.$$.context : options.context ? Object.entries(options.context) : []),
+		context: new Map(parent_component ? parent_component.$$.context : options.context || []),
 
 		// everything else
 		callbacks: blank_object(),

test/runtime/samples/constructor-pass-context/_config.js

@@ -5,10 +5,10 @@ export default {
 		const called = [];
 		const component = new Component({
 			target,
-			context: {
-				key: 'svelte',
-				fn: (value) => called.push(value)
-			}
+			context: new Map([
+				['key', 'svelte'],
+				['fn', (value) => called.push(value)]
+			])
 		});
 		assert.htmlEqual(target.innerHTML, '<div>svelte</div><button></button>');