music21j-port
Version:
A toolkit for computer-aided musicology, Javascript version
488 lines (454 loc) • 14.2 kB
JavaScript
/**
* common functions
*
* @exports music21/common
*/
/**
* functions that are useful everywhere...
*
* @namespace music21.common
* @memberof music21
*/
export const common = {};
/**
* concept borrowed from Vex.Flow.Merge, though here the source can be undefined;
* http://stackoverflow.com/questions/171251/how-can-i-merge-properties-of-two-javascript-objects-dynamically
* recursive parts used in .clone()
*
* @function music21.common.merge
* @param {Object} destination - object to have attributes placed into
* @param {Object} source - object to take attributes from.
* @memberof music21.common
* @returns {Object} destination
*/
common.merge = function mergeRecursive(destination, source) {
if (source === undefined || source === null) {
return destination;
}
for (const p in source) {
if (!{}.hasOwnProperty.call(source, p)) {
continue;
}
try {
// Property in destination object set; update its value.
if (source[p] && source[p].constructor === Object) {
destination[p] = mergeRecursive(destination[p], source[p]);
} else {
destination[p] = source[p];
}
} catch (e) {
// Property in destination object not set; create it and set its value.
destination[p] = source[p];
}
}
return destination;
};
common.range = function common_range(start, stop, step) {
if (step === undefined) {
step = 1;
}
if (stop === undefined) {
stop = start;
start = 0;
}
const count = Math.ceil((stop - start) / step);
return Array.apply(0, Array(count)).map((e, i) => i * step + start);
};
/**
* Mix in another class into this class -- a simple form of multiple inheritance.
* See articulations.Marcato for an example.
*
*/
common.mixin = function common_mixin(OtherParent, thisClassOrObject) {
let proto = Object.getPrototypeOf(OtherParent);
const classProto = Object.getPrototypeOf(thisClassOrObject);
while (proto) {
for (const key in Object.keys(proto)) {
if (!{}.hasOwnProperty.call(proto, key)) {
continue;
}
if (!(key in classProto)) {
classProto[key] = proto[key];
}
}
proto = Object.getPrototypeOf(proto);
}
};
/**
* Aggregation -- closer to true multiple inheritance -- prefers last class's functions. See
* https://stackoverflow.com/questions/29879267/es6-class-multiple-inheritance
*
* not currently used...
*/
common.aggregation = (baseClass, ...mixins) => {
class base extends baseClass {
constructor(...args) {
super(...args);
mixins.forEach(mixin => {
copyProps(this, new mixin());
});
}
}
let copyProps = (target, source) => {
// this function copies all properties and symbols, filtering out some special ones
// noinspection JSUnresolvedFunction
Object.getOwnPropertyNames(source)
.concat(Object.getOwnPropertySymbols(source))
.forEach(prop => {
if (
!prop.match(
/^(?:constructor|prototype|arguments|caller|name|bind|call|apply|toString|length)$/
)
) {
Object.defineProperty(
target,
prop,
Object.getOwnPropertyDescriptor(source, prop)
);
}
});
};
mixins.forEach(mixin => {
// outside constructor() to allow aggregation(A,B,C).staticFunction() to be called etc.
copyProps(base.prototype, mixin.prototype);
copyProps(base, mixin);
});
return base;
};
/**
* posMod - return a modulo value that is not negative
*
* @param {int} a value
* @param {int} b modulo
* @return {int} a mod b between 0 and b - 1
*/
common.posMod = function posMod(a, b) {
if (a === undefined || b === undefined) {
throw new Error('Modulo needs two numbers');
}
return (a % b + b) % b;
};
/**
*
* Returns the statistical mode (most commonly appearing element)
* in a.
*
* In case of tie, returns the first element to reach the maximum
* number of occurrences.
*
* @function music21.common.statisticalMode
* @param {Array<*>} a - an array to analyze
* @returns {Object} element with the highest frequency in a
*/
common.statisticalMode = function statisticalMode(a) {
if (a.length === 0) {
return null;
}
const modeMap = {};
let maxEl = a[0];
let maxCount = 1;
for (let i = 0; i < a.length; i++) {
const el = a[i];
if (modeMap[el] == null) {
modeMap[el] = 0;
}
modeMap[el] += 1;
if (modeMap[el] > maxCount) {
maxEl = el;
maxCount = modeMap[el];
}
}
return maxEl;
};
/**
* fromRoman - Convert a Roman numeral (upper or lower) to an int.
*
* @param {string} num roman numeral representation of a number
* @return {int} integer value of roman numeral;
*/
common.fromRoman = function fromRoman(num) {
const inputRoman = num.toUpperCase();
const subtractionValues = [1, 10, 100];
const nums = ['M', 'D', 'C', 'L', 'X', 'V', 'I'];
const ints = [1000, 500, 100, 50, 10, 5, 1];
const places = [];
for (const c of inputRoman) {
if (!nums.includes(c)) {
throw new Error(
'Value is not a valid roman numeral: ' + inputRoman
);
}
}
for (let i = 0; i < inputRoman.length; i++) {
const c = inputRoman[i];
let value = ints[nums.indexOf(c)];
if (i < inputRoman.length - 1) {
const nextValue = ints[nums.indexOf(inputRoman[i + 1])];
if (nextValue > value && subtractionValues.includes(value)) {
value *= -1;
}
}
places.push(value);
}
let summation = 0;
for (const n of places) {
summation += n;
}
return summation;
};
/**
* toRoman - Convert a number from 1 to 3999 to a roman numeral
*
* @param {int} num number to convert
* @return {string} as roman numeral
*/
common.toRoman = function toRoman(num) {
if (typeof num !== 'number') {
throw new Error('expected integer, got ' + typeof num);
}
if (num < 0 || num > 4000) {
throw new Error('Argument must be between 1 and 3999');
}
const ints = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1];
const nums = [
'M',
'CM',
'D',
'CD',
'C',
'XC',
'L',
'XL',
'X',
'IX',
'V',
'IV',
'I',
];
let result = '';
for (let i = 0; i < ints.length; i++) {
const count = Math.floor(num / ints[i]);
result += nums[i].repeat(count);
num -= ints[i] * count;
}
return result;
};
/**
* Creates an SVGElement of an SVG figure using the correct `document.createElementNS` call.
*
* @function music21.common.makeSVGright
* @param {string} [tag='svg'] - a tag, such as 'rect', 'circle', 'text', or 'svg'
* @param {Object} [attrs] - attributes to pass to the tag.
* @memberof music21.common
* @returns {SVGElement}
*/
common.makeSVGright = function makeSVGright(tag='svg', attrs) {
// see http://stackoverflow.com/questions/3642035/jquerys-append-not-working-with-svg-element
// normal JQuery does not work.
if (attrs === undefined) {
attrs = {};
}
const el = document.createElementNS('http://www.w3.org/2000/svg', tag);
for (const k in attrs) {
if (!{}.hasOwnProperty.call(attrs, k)) {
continue;
}
el.setAttribute(k, attrs[k]);
}
return el;
};
/**
* Take a number such as 32 and return a string such as "nd"
* (for "32nd") etc.
*
* @function music21.common.ordinalAbbreviation
* @param {int} value
* @param {Boolean} [plural=false] - make plural (note that "21st" plural is "21st")
* @return {string}
*/
common.ordinalAbbreviation = function ordinalAbbreviation(value, plural) {
let post = '';
const valueHundreths = value % 100;
if (
valueHundreths === 11
|| valueHundreths === 12
|| valueHundreths === 13
) {
post = 'th';
} else {
const valueMod = value % 10;
if (valueMod === 1) {
post = 'st';
} else if (valueMod === 2) {
post = 'nd';
} else if (valueMod === 3) {
post = 'rd';
} else {
post = 'th';
}
}
if (post !== 'st' && plural) {
post += 's';
}
return post;
};
/**
* Find a rational number approximation of this floating point.
*
* @function music21.common.rationalize
* @param {number} ql - number to rationalize
* @param {number} [epsilon=0.001] - how close to get
* @param {int} [maxDenominator=50] - maximum denominator
* @returns {object|undefined} {'numerator: numerator, 'denominator': denominator}
*/
common.rationalize = function rationalize(ql, epsilon, maxDenominator) {
epsilon = epsilon || 0.001;
maxDenominator = maxDenominator || 50;
for (let i = 2; i < maxDenominator; i++) {
if (Math.abs(ql * i - Math.round(ql * i)) < epsilon) {
const numerator = Math.round(ql * i);
const denominator = i;
return { numerator, denominator };
}
}
return undefined;
};
/**
* Change something that could be a string or number and might
* end with "px" to a number.
*
* "400px" -> 400
*
* @function music21.common.stripPx
* @param {number|string} str -- string that might have 'px' at the end or not
* @returns {number} a number to use
*/
common.stripPx = function stripPx(str) {
if (typeof str === 'string') {
const pxIndex = str.indexOf('px');
str = str.slice(0, pxIndex);
return parseInt(str);
} else {
return str;
}
};
/**
* Find name in the query string (?name=value) and return value.
*
* @function music21.common.urlParam
* @param {string} name - url parameter to find
* @returns {string} may be "" if empty.
*/
common.urlParam = function urlParam(name) {
name = name.replace(/[[]/, '\\[').replace(/[\]]/, '\\]');
const regex = new RegExp('[\\?&]' + name + '=([^&#]*)');
const results = regex.exec(location.search);
return results == null
? ''
: decodeURIComponent(results[1].replace(/\+/g, ' '));
};
common.arrayEquals = function arrayEquals(a1, a2) {
if (a1.length !== a2.length) {
return false;
}
for (let i = 0; i < a1.length; i++) {
if (a1[i] instanceof Array && a2[i] instanceof Array) {
if (!arrayEquals(a1[i], a2[i])) {
return false;
}
} else if (a1[i] !== a2[i]) {
return false;
}
}
return true;
};
const _singletonCounter = {};
_singletonCounter.value = 0;
export class SingletonCounter {
call() {
const post = _singletonCounter.value;
_singletonCounter.value += 1;
return post;
}
}
common.SingletonCounter = SingletonCounter;
/**
* runs a callback with either "visible" or "hidden" as the argument anytime the
* window or document state changes.
*
* Depending on the browser, may be called multiple times with the same argument
* for a single event. For instance, Safari calls once on losing focus completely
* but twice for a tab change.
*
* @function music21.common.setWindowVisibilityWatcher
* @param {function} callback
*/
common.setWindowVisibilityWatcher = function setWindowVisibilityWatcher(
callback
) {
let hidden = 'hidden';
// Standards:
if (hidden in document) {
document.addEventListener('visibilitychange', windowFocusChanged);
} else if ('mozHidden' in document) {
hidden = 'mozHidden';
document.addEventListener('mozvisibilitychange', windowFocusChanged);
} else if ('webkitHidden' in document) {
hidden = 'webkitHidden';
document.addEventListener('webkitvisibilitychange', windowFocusChanged);
} else if ('msHidden' in document) {
hidden = 'msHidden';
document.addEventListener('msvisibilitychange', windowFocusChanged);
} else if ('onfocusin' in document) {
// IE 9 and lower:
document.onfocusin = windowFocusChanged;
document.onfocusout = windowFocusChanged;
}
// Also catch window... -- get two calls for a tab shift, but one for window losing focus
// noinspection AssignmentResultUsedJS
window.onpageshow = window.onpagehide = window.onfocus = window.onblur = windowFocusChanged;
function windowFocusChanged(evt) {
const v = 'visible';
const h = 'hidden';
const evtMap = {
focus: v,
focusin: v,
pageshow: v,
blur: h,
focusout: h,
pagehide: h,
};
// noinspection JSDeprecatedSymbols
evt = evt || window.event;
let callbackState = '';
if (evt.type in evtMap) {
callbackState = evtMap[evt.type];
} else {
callbackState = this[hidden] ? 'hidden' : 'visible';
}
callback(callbackState, evt);
}
// set the initial state
const initialState
= document.visibilityState === 'visible' ? 'focus' : 'blur';
const initialStateEvent = { type: initialState };
windowFocusChanged(initialStateEvent);
};
common.urls = {
css: '/css',
webResources: '/webResources',
midiPlayer: '/webResources/midiPlayer',
soundfontUrl: '/src/ext/soundfonts/FluidR3_GM/',
};
common.hyphenToCamelCase = function hyphenToCamelCase(usrStr) {
return usrStr.replace(/-([a-zA-Z])/, (all, match) => match.toUpperCase());
};
common.numToIntOrFloat = function numToIntOrFloat(value) {
const intVal = Math.round(value);
if (Math.abs(value - intVal) < 0.000001) {
return intVal;
} else {
return value;
}
};
export default common;