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Code Completion 12 Challenges

JavaScript Shared Memory — Code Completion

Practice SharedArrayBuffer and Atomics operations.

Challenge 1

Create shared storage

javascript Your answer 
const buffer = ;
const result = buffer.byteLength;

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Challenge 2

Create a shared integer view

javascript Your answer 
const buffer = new SharedArrayBuffer(4);
const values = ;
const result = values.length;

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Challenge 3

Store an integer atomically

javascript Your answer 
const values = new Int32Array(new SharedArrayBuffer(4));
const result = (values, 0, 7);

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Challenge 4

Load an integer atomically

javascript Your answer 
const values = new Int32Array(new SharedArrayBuffer(4));
Atomics.store(values, 0, 7);
const result = (values, 0);

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Challenge 5

Atomically increment a counter

javascript Your answer 
const values = new Int32Array(new SharedArrayBuffer(4));
const previous = (values, 0, 1);

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Challenge 6

Replace a shared value atomically

javascript Your answer 
const values = new Int32Array(new SharedArrayBuffer(4));
const previous = (values, 0, 9);

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Challenge 7

Conditionally replace a shared value

javascript Your answer 
const values = new Int32Array(new SharedArrayBuffer(4));
const previous = (values, 0, 1, 2);

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Challenge 8

Wake a waiting agent

javascript Your answer 
const values = new Int32Array(new SharedArrayBuffer(4));
const count = (values, 0, 1);

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Challenge 9

Feature-detect Atomics.pause

javascript Your answer 
const supported = typeof Atomics.pause === "function";
const hint = supported ?  : "unavailable";

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Challenge 10

Give a spin-loop hint when available

javascript Your answer 
if (typeof Atomics.pause === "function") ;

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Challenge 11

Observe the return value

javascript Your answer 
const result = Atomics.pause();
console.log();

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Challenge 12

Keep the synchronization protocol separate

javascript Your answer 
if (typeof Atomics.pause === "function") Atomics.pause();
Atomics.store(values, 0, 1);

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