apply() — svelte Function Reference

Architecture documentation for the apply() function in batch.js from the svelte codebase.

Function javascript ClientRuntime Reactivity calls 1 called by 5

Entity Profile

ClientRuntime→ Reactivity→ apply() — svelte Function Reference

Dependency Diagram

graph TD
  58e25076_0e70_68a7_dbf9_e13ef9845ff2["apply()"]
  517c145b_769f_b163_6854_d8f2a4412e11["Batch"]
  58e25076_0e70_68a7_dbf9_e13ef9845ff2 -->|defined in| 517c145b_769f_b163_6854_d8f2a4412e11
  3ceb9b1c_7062_d75e_744a_fd12a80dfdc9["reconcile()"]
  3ceb9b1c_7062_d75e_744a_fd12a80dfdc9 -->|calls| 58e25076_0e70_68a7_dbf9_e13ef9845ff2
  05511be0_1e56_3876_59e2_7350fc912bb9["process()"]
  05511be0_1e56_3876_59e2_7350fc912bb9 -->|calls| 58e25076_0e70_68a7_dbf9_e13ef9845ff2
  e2994140_cbea_e6ee_c66f_0adec4e39cd7["activate()"]
  e2994140_cbea_e6ee_c66f_0adec4e39cd7 -->|calls| 58e25076_0e70_68a7_dbf9_e13ef9845ff2
  dd2db25f_ec55_d3be_61b9_c180c4e4cbc8["batches()"]
  dd2db25f_ec55_d3be_61b9_c180c4e4cbc8 -->|calls| 58e25076_0e70_68a7_dbf9_e13ef9845ff2
  1edde895_4b1f_7b83_74c8_3640bf220ca9["run_test_variant()"]
  1edde895_4b1f_7b83_74c8_3640bf220ca9 -->|calls| 58e25076_0e70_68a7_dbf9_e13ef9845ff2
  63ee8247_ada4_9f1d_e139_0c1167cd5b1c["set()"]
  58e25076_0e70_68a7_dbf9_e13ef9845ff2 -->|calls| 63ee8247_ada4_9f1d_e139_0c1167cd5b1c
  style 58e25076_0e70_68a7_dbf9_e13ef9845ff2 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

packages/svelte/src/internal/client/reactivity/batch.js lines 536–553

	apply() {
		if (!async_mode_flag || (!this.is_fork && batches.size === 1)) return;

		// if there are multiple batches, we are 'time travelling' —
		// we need to override values with the ones in this batch...
		batch_values = new Map(this.current);

		// ...and undo changes belonging to other batches
		for (const batch of batches) {
			if (batch === this) continue;

			for (const [source, previous] of batch.previous) {
				if (!batch_values.has(source)) {
					batch_values.set(source, previous);
				}
			}
		}
	}