casing.js

(function(casing = "snake") {
  function convert(key, casing) {
    switch (casing) {
      case "snake":
        return key.replace(/([a-z0-9])([A-Z])/g, "$1_$2").toLowerCase();
      case "kebab":
        return key.replace(/([a-z0-9])([A-Z])/g, "$1-$2").toLowerCase();
      case "pascal":
        return key.charAt(0).toUpperCase() + key.slice(1);
      case "screaming":
        if (key === key.toUpperCase()) return key;
        return key.replace(/([a-z0-9])([A-Z])/g, "$1_$2").toUpperCase();
      default:
        return key;
    }
  }

  function patchCamelCase(proto, casing) {
    Object.getOwnPropertyNames(proto).forEach(function(key) {
      if (!/[A-Z]/.test(key)) return;
      var newKey = convert(key, casing);
      if (newKey in proto) return;
      var originalDesc = Object.getOwnPropertyDescriptor(proto, key);
      if (!originalDesc) return;
      var aliasDescriptor;
      if ("value" in originalDesc) {
        aliasDescriptor = {
          get: function() { return originalDesc.value; },
          set: function(val) { originalDesc.value = val; },
          configurable: true,
          enumerable: true
        };
      } else {
        aliasDescriptor = {
          get: originalDesc.get ? function() { return originalDesc.get.call(this); } : undefined,
          set: originalDesc.set ? function(val) { return originalDesc.set.call(this, val); } : undefined,
          configurable: true,
          enumerable: true
        };
      }
      try {
        Object.defineProperty(proto, newKey, aliasDescriptor);
      } catch (e) {}
      if (originalDesc.configurable) {
        try {
          Object.defineProperty(proto, key, Object.assign({}, originalDesc, { enumerable: false }));
        } catch (e) {}
      }
    });
  }

  var prototypes = [
    typeof window !== "undefined" ? window.__proto__ : null,
    typeof Document !== "undefined" ? Document.prototype : null,
    typeof DocumentFragment !== "undefined" ? DocumentFragment.prototype : null,
    typeof Element !== "undefined" ? Element.prototype : null,
    typeof Node !== "undefined" ? Node.prototype : null,
    typeof Event !== "undefined" ? Event.prototype : null,
    Array.prototype,
    Set.prototype,
    Map.prototype,
    Function.prototype,
    String.prototype,
    Number.prototype,
    Boolean.prototype,
    RegExp.prototype
  ].filter(function(p) { return p; });

  prototypes.forEach(function(proto) {
    patchCamelCase(proto, casing);
  });
})("snake");