176 lines
3.7 KiB
Markdown
176 lines
3.7 KiB
Markdown
# js
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Provides functions for introspecting and configuring the QuickJS runtime engine.
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Includes debug info, memory usage, GC controls, code evaluation, etc.
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### cycle_hook(callback) <sub>function</sub>
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or undefined to remove the callback.
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Register or remove a hook function that QuickJS calls once per execution cycle. If the callback
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is set, it receives a single argument (an optional object/value describing the cycle). If callback
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is undefined, the hook is removed.
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**callback**: A function to call each time QuickJS completes a "cycle" (internal VM loop),
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**Returns**: None
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### dump_shapes() <sub>function</sub>
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Use this for internal debugging of object shapes.
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**Returns**: A debug string describing the internal shape hierarchy used by QuickJS.
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### dump_atoms() <sub>function</sub>
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known by QuickJS. Helpful for diagnosing memory usage or potential key collisions.
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**Returns**: A debug string listing all currently registered atoms (internal property keys/symbols)
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### dump_class() <sub>function</sub>
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Shows how many objects of each class exist, useful for advanced memory or performance profiling.
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**Returns**: A debug string describing the distribution of JS object classes in the QuickJS runtime.
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### dump_objects() <sub>function</sub>
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useful for debugging memory leaks or object lifetimes.
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**Returns**: A debug string listing certain internal QuickJS objects and their references,
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### dump_type_overheads() <sub>function</sub>
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Displays memory usage breakdown for different internal object types.
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**Returns**: A debug string describing the overheads for various JS object types in QuickJS.
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### stack_info() <sub>function</sub>
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Internal debugging utility to examine call stack details.
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**Returns**: An object or string describing the runtime's current stack usage and capacity.
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### calc_mem(value) <sub>function</sub>
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Compute the approximate size of a single JS value in memory. This is a best-effort estimate.
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**value**: A JavaScript value to analyze.
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**Returns**: Approximate memory usage (in bytes) of that single value.
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### mem() <sub>function</sub>
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including total allocated bytes, object counts, and more.
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Retrieve an overview of the runtime’s memory usage.
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**Returns**: An object containing a comprehensive snapshot of memory usage for the current QuickJS runtime,
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### mem_limit(bytes) <sub>function</sub>
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Set the upper memory limit for the QuickJS runtime. Exceeding this limit may cause operations to
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fail or throw errors.
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**bytes**: The maximum memory (in bytes) QuickJS is allowed to use.
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**Returns**: None
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### gc_threshold(bytes) <sub>function</sub>
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Set the threshold (in bytes) for QuickJS to perform an automatic GC pass when memory usage surpasses it.
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**bytes**: The threshold (in bytes) at which the engine triggers automatic garbage collection.
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**Returns**: None
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### max_stacksize(bytes) <sub>function</sub>
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Set the maximum stack size for QuickJS. If exceeded, the runtime may throw a stack overflow error.
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**bytes**: The maximum allowed stack size (in bytes) for QuickJS.
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**Returns**: None
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### memstate() <sub>function</sub>
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Gives a quick overview of the memory usage, including malloc size and other allocations.
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**Returns**: A simpler memory usage object (malloc sizes, etc.) for the QuickJS runtime.
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### gc() <sub>function</sub>
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Force an immediate, full garbage collection pass, reclaiming unreachable memory.
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**Returns**: None
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### eval(src, filename) <sub>function</sub>
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Execute a string of JavaScript code in the current QuickJS context.
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**src**: A string of JavaScript source code to evaluate.
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**filename**: (Optional) A string for the filename or label, used in debugging or stack traces.
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**Returns**: The result of evaluating the given source code.
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