regex.test vs known string.startsWith

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regex.test vs known string.startsWith

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jsBenchIt.json

{"title":"regex.test vs known string.startsWith","initialization":"const arr = [];\nconst prefixes = ['startswith', 'emojis', 'custom', null];\n\nfor (let i = 0, j = 100; i < j; i++) {\n  const prefix = prefixes[Math.floor(Math.random() * prefixes.length)];\n  const id = Math.round(Math.random() * 999999999);\n  arr.push({\n    id: prefix\n      ? `${prefix}-${id}`\n      : id\n  });\n}\n\nconst regex = /^(startswith|emojis|custom)-/;\n\nconst funct = id => {\n  if (typeof id !== 'string') return false;\n  return id.startsWith('startswith-') ||\n    id.startsWith('emojis-') ||\n    id.startsWith('custom-');\n};\n\nconst expected = arr.reduce((acc, curr) => {\n  return funct(curr.id) ? (acc + 1) : acc;\n}, 0);\n\nconst check = count => {\n  if (count !== expected) {\n    throw new Error('Final count mismatch');\n  }\n}","setup":"// runs before each test","tests":[{"name":"test 1","code":"let found = 0;\nfor (let i = 0; i < arr.length; i++) {\n  if (regex.test(arr[i].id)) found++;\n}\ncheck(found);","results":{"aborted":false,"count":11408,"cycles":5,"hz":137383.2537674571,"stats":{"moe":1.2823126600884092e-7,"rme":1.7616828559014888,"sem":6.542411531063313e-8,"deviation":4.895892486503611e-7,"mean":0.000007278907527497189,"variance":2.3969763239402514e-13,"numSamples":56},"times":{"cycle":0.08303777707368792,"elapsed":7.434,"period":0.000007278907527497189,"timeStamp":1665610734786}},"platforms":{"Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:105.0) Gecko/20100101 Firefox/105.0":{"aborted":false,"count":11408,"cycles":5,"hz":137383.2537674571,"stats":{"moe":1.2823126600884092e-7,"rme":1.7616828559014888,"sem":6.542411531063313e-8,"deviation":4.895892486503611e-7,"mean":0.000007278907527497189,"variance":2.3969763239402514e-13,"numSamples":56},"times":{"cycle":0.08303777707368792,"elapsed":7.434,"period":0.000007278907527497189,"timeStamp":1665610734786}}}},{"name":"test 2","code":"let found = 0;\nfor (let i = 0; i < arr.length; i++) {\n  if (funct(arr[i].id)) found++;\n}\ncheck(found);","results":{"aborted":false,"count":101577,"cycles":4,"hz":1209238.6975519592,"stats":{"moe":1.2017994694388791e-8,"rme":1.4532624251429058,"sem":6.1316299461167305e-9,"deviation":4.6292790911529426e-8,"mean":8.2696658817192e-7,"variance":2.1430224903785813e-15,"numSamples":57},"times":{"cycle":0.08400078512673911,"elapsed":7.148,"period":8.2696658817192e-7,"timeStamp":1665610742227}},"platforms":{"Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:105.0) Gecko/20100101 Firefox/105.0":{"aborted":false,"count":101577,"cycles":4,"hz":1209238.6975519592,"stats":{"moe":1.2017994694388791e-8,"rme":1.4532624251429058,"sem":6.1316299461167305e-9,"deviation":4.6292790911529426e-8,"mean":8.2696658817192e-7,"variance":2.1430224903785813e-15,"numSamples":57},"times":{"cycle":0.08400078512673911,"elapsed":7.148,"period":8.2696658817192e-7,"timeStamp":1665610742227}}}}]}