91 lines
2.5 KiB
Plaintext
91 lines
2.5 KiB
Plaintext
/**
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @flow strict-local
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* @format
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* @oncall react_native
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*/
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'use strict';
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/* eslint-disable no-redeclare */
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// A type representing 0-based offsets.
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export opaque type Number0 = number;
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// A type representing 1-based offsets.
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export opaque type Number1 = number;
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// Add two offsets or numbers.
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declare function add(a: Number1, b: number): Number1;
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declare function add(a: number, b: Number1): Number1;
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declare function add(a: Number0, b: number): Number0;
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declare function add(a: number, b: Number0): Number0;
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declare function add(a: Number1, b: Number0): Number1;
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declare function add(a: Number0, b: Number1): Number1;
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declare function add(a: Number0, b: Number0): Number0;
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function add(a: number, b: number): number {
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return a + b;
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}
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// Subtract a number or 0-based offset from a 1/0-based offset.
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declare function sub(a: Number1, b: number): Number1;
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declare function sub(a: Number0, b: number): Number0;
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declare function sub(a: number, b: Number0): Number0;
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declare function sub(a: Number0, b: number): Number0;
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declare function sub(a: Number1, b: Number0): Number1;
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declare function sub(a: Number0, b: Number0): Number0;
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declare function sub(a: Number1, b: Number1): Number0;
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function sub(a: number, b: number): number {
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return a - b;
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}
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// Get the underlying number of a 0-based offset, casting away the opaque type.
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declare function get0(x: Number0): number;
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declare function get0(x: void | null): void | null;
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function get0(x: number): number {
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return x;
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}
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// Get the underlying number of a 1-based offset, casting away the opaque type.
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declare function get1(x: Number1): number;
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declare function get1(x: void | null): void | null;
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function get1(x: number): number {
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return x;
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}
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// Add 1 to a 0-based offset, thus converting it to 1-based.
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function add1(x: Number0 | number): Number1 {
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return x + 1;
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}
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// Subtract 1 from a 1-based offset, thus converting it to 0-based.
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function sub1(x: Number1): Number0 {
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return x - 1;
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}
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// Negate a 0-based offset.
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function neg(x: Number0): Number0 {
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return -x;
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}
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// Cast a number to a 0-based offset.
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function add0(x: number): Number0 {
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return x;
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}
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// Increment a 0-based offset.
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declare function inc(a: Number0): Number0;
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// Increment a 1-based offset.
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declare function inc(a: Number1): Number1;
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function inc(x: number): number {
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return x + 1;
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}
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module.exports = {add, get0, get1, add1, sub1, sub, neg, add0, inc};
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