feat(time-slots): add basic generation strategy

package.json

@@ -62,5 +62,9 @@
   "files": [
     "dist/**/*"
   ],
-  "dependencies": {}
+  "dependencies": {
+    "@types/ramda": "^0.27.25",
+    "moment": "^2.29.1",
+    "ramda": "^0.27.1"
+  }
 }

src/__tests__/slots.test.ts

@@ -0,0 +1,49 @@
+import moment, { Moment } from "moment";
+
+import { addInterval, Interval, slots } from "../slots";
+
+describe("slots", () => {
+  const interval: Interval = { amount: 30, unit: "minutes" };
+  const d1 = moment();
+  const d2 = addInterval(interval)(d1); // d1 + 30m
+  const d3 = addInterval(interval)(d2); // d2 + 30m = d1 + 60m
+  const start = d1;
+
+  const geq = (d: Moment) => (c: Moment): boolean => c >= d;
+
+  it("generate a single time slot", () => {
+    const gen = slots(interval)([])(start);
+
+    expect(gen.next().value).toEqual([start.format("HH:mm")]);
+  });
+
+  it("generate subsequent time slots", () => {
+    const gen = slots(interval)([])(start);
+
+    expect(gen.next().value).toEqual([start.format("HH:mm")]);
+    expect(gen.next().value).toEqual([addInterval(interval)(start).format("HH:mm")]);
+  });
+
+  it("do not generate time slots if constraints always fail", () => {
+    const gen = slots(interval)([() => false])(start);
+
+    expect(gen.next().value).toEqual([]);
+  });
+
+  it("do not generate time slots if a constraint is failing", () => {
+    const gen = slots(interval)([geq(d2)])(start);
+
+    expect(gen.next().value).toEqual([]);
+    expect(gen.next().value).toEqual([d2.format("HH:mm")]);
+    expect(gen.next().value).not.toEqual([]);
+  });
+
+  it("do not generate time slots if costraints are failing", () => {
+    const gen = slots(interval)([geq(d2), geq(d3)])(start);
+
+    expect(gen.next().value).toEqual([]);
+    expect(gen.next().value).toEqual([]);
+    expect(gen.next().value).toEqual([d3.format("HH:mm")]);
+    expect(gen.next().value).not.toEqual([]);
+  });
+});

src/constraint.ts

@@ -0,0 +1,7 @@
+import { Moment } from "moment";
+import * as R from "ramda";
+
+export type Constraint = (current: Moment) => boolean;
+
+export const validate = (constraints: Constraint[]) => (current: Moment) =>
+  R.all(R.identity, R.map(R.applyTo(current), constraints));

src/slots.ts

@@ -0,0 +1,32 @@
+import moment, { Moment } from "moment";
+import { Constraint, validate } from "./constraint";
+
+export type Interval = {
+  amount: moment.DurationInputArg1;
+  unit: moment.DurationInputArg2;
+};
+
+export type Slot = string;
+
+export const addInterval = (interval: Interval) => (m: Moment): Moment => m.clone().add(interval.amount, interval.unit);
+
+export const slots = (interval: Interval) => (constraints: Constraint[]) => (start: Moment) => {
+  return (function* () {
+    let newStart = start;
+
+    while (true) {
+      yield one(constraints)(newStart);
+      newStart = addInterval(interval)(newStart);
+    }
+  })();
+};
+
+export const one = (constraints: Constraint[]) => (start: Moment): string[] => {
+  const current = moment(start, "HH:mm");
+
+  if (validate(constraints)(current)) {
+    return [current.format("HH:mm")];
+  }
+
+  return [];
+};

yarn.lock

@@ -994,6 +994,13 @@
   resolved "https://registry.yarnpkg.com/@types/prettier/-/prettier-2.0.0.tgz#dc85454b953178cc6043df5208b9e949b54a3bc4"
   integrity sha512-/rM+sWiuOZ5dvuVzV37sUuklsbg+JPOP8d+nNFlo2ZtfpzPiPvh1/gc8liWOLBqe+sR+ZM7guPaIcTt6UZTo7Q==
 
+"@types/ramda@^0.27.25":
+  version "0.27.25"
+  resolved "https://registry.yarnpkg.com/@types/ramda/-/ramda-0.27.25.tgz#8b9b1910f93d3c3344ccfad1641f9332904f9eb5"
+  integrity sha512-D6gYQumFrGwDa0K2XqUIbktTAnQ/KBnbtL+IpXbpaiJJ1qnmfDZXe0diJC7LRQf7NvjjgxceQmv7YnL/1xjw6A==
+  dependencies:
+    ts-toolbelt "^6.3.3"
+
 "@types/retry@^0.12.0":
   version "0.12.0"
   resolved "https://registry.yarnpkg.com/@types/retry/-/retry-0.12.0.tgz#2b35eccfcee7d38cd72ad99232fbd58bffb3c84d"
@@ -5421,6 +5428,11 @@ modify-values@^1.0.0:
   resolved "https://registry.yarnpkg.com/modify-values/-/modify-values-1.0.1.tgz#b3939fa605546474e3e3e3c63d64bd43b4ee6022"
   integrity sha512-xV2bxeN6F7oYjZWTe/YPAy6MN2M+sL4u/Rlm2AHCIVGfo2p1yGmBHQ6vHehl4bRTZBdHu3TSkWdYgkwpYzAGSw==
 
+moment@^2.29.1:
+  version "2.29.1"
+  resolved "https://registry.yarnpkg.com/moment/-/moment-2.29.1.tgz#b2be769fa31940be9eeea6469c075e35006fa3d3"
+  integrity sha512-kHmoybcPV8Sqy59DwNDY3Jefr64lK/by/da0ViFcuA4DH0vQg5Q6Ze5VimxkfQNSC+Mls/Kx53s7TjP1RhFEDQ==
+
 move-concurrently@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/move-concurrently/-/move-concurrently-1.0.1.tgz#be2c005fda32e0b29af1f05d7c4b33214c701f92"
@@ -6552,6 +6564,11 @@ qw@~1.0.1:
   resolved "https://registry.yarnpkg.com/qw/-/qw-1.0.1.tgz#efbfdc740f9ad054304426acb183412cc8b996d4"
   integrity sha1-77/cdA+a0FQwRCassYNBLMi5ltQ=
 
+ramda@^0.27.1:
+  version "0.27.1"
+  resolved "https://registry.yarnpkg.com/ramda/-/ramda-0.27.1.tgz#66fc2df3ef873874ffc2da6aa8984658abacf5c9"
+  integrity sha512-PgIdVpn5y5Yns8vqb8FzBUEYn98V3xcPgawAkkgj0YJ0qDsnHCiNmZYfOGMgOvoB0eWFLpYbhxUR3mxfDIMvpw==
+
 rc@^1.0.1, rc@^1.1.6, rc@^1.2.8:
   version "1.2.8"
   resolved "https://registry.yarnpkg.com/rc/-/rc-1.2.8.tgz#cd924bf5200a075b83c188cd6b9e211b7fc0d3ed"
@@ -7828,6 +7845,11 @@ ts-jest@26.4.1:
     semver "7.x"
     yargs-parser "20.x"
 
+ts-toolbelt@^6.3.3:
+  version "6.15.5"
+  resolved "https://registry.yarnpkg.com/ts-toolbelt/-/ts-toolbelt-6.15.5.tgz#cb3b43ed725cb63644782c64fbcad7d8f28c0a83"
+  integrity sha512-FZIXf1ksVyLcfr7M317jbB67XFJhOO1YqdTcuGaq9q5jLUoTikukZ+98TPjKiP2jC5CgmYdWWYs0s2nLSU0/1A==
+
 tslib@^1.8.1:
   version "1.11.0"
   resolved "https://registry.yarnpkg.com/tslib/-/tslib-1.11.0.tgz#f1f3528301621a53220d58373ae510ff747a66bc"