Initial project upload

frontend/node_modules/spacetime/src/methods/set/walk.js

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+/* eslint-disable no-console */
+import ms from '../../data/milliseconds.js'
+
+//basically, step-forward/backward until js Date object says we're there.
+const walk = (s, n, fn, unit, previous) => {
+  const current = s.d[fn]()
+  if (current === n) {
+    return //already there
+  }
+  const startUnit = previous === null ? null : s.d[previous]()
+  const original = s.epoch
+  //try to get it as close as we can
+  const diff = n - current
+  s.epoch += ms[unit] * diff
+  //DST edge-case: if we are going many days, be a little conservative
+  // console.log(unit, diff)
+  if (unit === 'day') {
+    // s.epoch -= ms.minute
+    //but don't push it over a month
+    if (Math.abs(diff) > 28 && n < 28) {
+      s.epoch += ms.hour
+    }
+  }
+  // 1st time: oops, did we change previous unit? revert it.
+  if (previous !== null && startUnit !== s.d[previous]()) {
+    // console.warn('spacetime warning: missed setting ' + unit)
+    s.epoch = original
+    // s.epoch += ms[unit] * diff * 0.89 // maybe try and make it close...?
+  }
+  //repair it if we've gone too far or something
+  //(go by half-steps, just in case)
+  const halfStep = ms[unit] / 2
+  while (s.d[fn]() < n) {
+    s.epoch += halfStep
+  }
+
+  while (s.d[fn]() > n) {
+    s.epoch -= halfStep
+  }
+  // 2nd time: did we change previous unit? revert it.
+  if (previous !== null && startUnit !== s.d[previous]()) {
+    // console.warn('spacetime warning: missed setting ' + unit)
+    s.epoch = original
+  }
+}
+//find the desired date by a increment/check while loop
+const units = {
+  year: {
+    valid: (n) => n > -4000 && n < 4000,
+    walkTo: (s, n) => walk(s, n, 'getFullYear', 'year', null)
+  },
+  month: {
+    valid: (n) => n >= 0 && n <= 11,
+    walkTo: (s, n) => {
+      const d = s.d
+      const current = d.getMonth()
+      const original = s.epoch
+      const startUnit = d.getFullYear()
+      if (current === n) {
+        return
+      }
+      //try to get it as close as we can..
+      const diff = n - current
+      s.epoch += ms.day * (diff * 28) //special case
+      //oops, did we change the year? revert it.
+      if (startUnit !== s.d.getFullYear()) {
+        s.epoch = original
+      }
+      //increment by day
+      while (s.d.getMonth() < n) {
+        s.epoch += ms.day
+      }
+      while (s.d.getMonth() > n) {
+        s.epoch -= ms.day
+      }
+    }
+  },
+  date: {
+    valid: (n) => n > 0 && n <= 31,
+    walkTo: (s, n) => walk(s, n, 'getDate', 'day', 'getMonth')
+  },
+  hour: {
+    valid: (n) => n >= 0 && n < 24,
+    walkTo: (s, n) => walk(s, n, 'getHours', 'hour', 'getDate')
+  },
+  minute: {
+    valid: (n) => n >= 0 && n < 60,
+    walkTo: (s, n) => walk(s, n, 'getMinutes', 'minute', 'getHours')
+  },
+  second: {
+    valid: (n) => n >= 0 && n < 60,
+    walkTo: (s, n) => {
+      //do this one directly
+      s.epoch = s.seconds(n).epoch
+    }
+  },
+  millisecond: {
+    valid: (n) => n >= 0 && n < 1000,
+    walkTo: (s, n) => {
+      //do this one directly
+      s.epoch = s.milliseconds(n).epoch
+    }
+  }
+}
+
+const walkTo = (s, wants) => {
+  const keys = Object.keys(units)
+  const old = s.clone()
+  for (let i = 0; i < keys.length; i++) {
+    const k = keys[i]
+    let n = wants[k]
+    if (n === undefined) {
+      n = old[k]()
+    }
+    if (typeof n === 'string') {
+      n = parseInt(n, 10)
+    }
+    //make-sure it's valid
+    if (!units[k].valid(n)) {
+      s.epoch = null
+      if (s.silent === false) {
+        console.warn('invalid ' + k + ': ' + n)
+      }
+      return
+    }
+    units[k].walkTo(s, n)
+  }
+  return
+}
+
+export default walkTo