> For the complete documentation index, see [llms.txt](https://docs.mapbox.com/mapbox-gl-js/ja/llms.txt) # Persist sources and layers when switching a map's base style This example shows how to persist [sources](https://docs.mapbox.com/style-spec/reference/sources/) and [layers](https://docs.mapbox.com/style-spec/reference/layers/) that were added via code when changing a map's [style](https://docs.mapbox.com/style-spec/). Since there is no basemap in Mapbox GL JS, developers often instantiate a map with a [Mapbox core style](https://docs.mapbox.com/api/maps/styles/#mapbox-styles) or a custom style created in [Mapbox Studio](https://www.mapbox.com/mapbox-studio), and then use [`addSource()` and `addLayer()`](https://docs.mapbox.com/mapbox-gl-js/ja/example/geojson-layer-in-stack/) to add additional data and layers. Changing the style (For example switching from [Streets](https://www.mapbox.com/maps/streets) to [Satellite](https://docs.mapbox.com/help/glossary/mapbox-satellite/)) is possible with [`setStyle()`](https://docs.mapbox.com/mapbox-gl-js/ja/example/setstyle/), but any sources and layers added after the initial load are lost. This example listens for the `style.load` event to trigger re-adding these additional sources and layers. The base-style-switching menu comes from the example [Change a map's style](https://docs.mapbox.com/mapbox-gl-js/ja/example/setstyle/), while the GeoJSON and location selection comes from the example [Add a line to a map using a GeoJSON source](https://docs.mapbox.com/mapbox-gl-js/ja/example/geojson-line/). > Example code: **JavaScript** ```html Persist sources and layers when switching a map's base style
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