constructor( binding, typeName, valueSize ) {

		/**
		 * The property binding.
		 *
		 * @type {PropertyBinding}
		 */
		this.binding = binding;

		/**
		 * The keyframe track value size.
		 *
		 * @type {number}
		 */
		this.valueSize = valueSize;

		let mixFunction,
			mixFunctionAdditive,
			setIdentity;

		// buffer layout: [ incoming | accu0 | accu1 | orig | addAccu | (optional work) ]
		//
		// interpolators can use .buffer as their .result
		// the data then goes to 'incoming'
		//
		// 'accu0' and 'accu1' are used frame-interleaved for
		// the cumulative result and are compared to detect
		// changes
		//
		// 'orig' stores the original state of the property
		//
		// 'add' is used for additive cumulative results
		//
		// 'work' is optional and is only present for quaternion types. It is used
		// to store intermediate quaternion multiplication results

		switch ( typeName ) {

			case 'quaternion':
				mixFunction = this._slerp;
				mixFunctionAdditive = this._slerpAdditive;
				setIdentity = this._setAdditiveIdentityQuaternion;

				this.buffer = new Float64Array( valueSize * 6 );
				this._workIndex = 5;
				break;

			case 'string':
			case 'bool':
				mixFunction = this._select;

				// Use the regular mix function and for additive on these types,
				// additive is not relevant for non-numeric types
				mixFunctionAdditive = this._select;

				setIdentity = this._setAdditiveIdentityOther;

				this.buffer = new Array( valueSize * 5 );
				break;

			default:
				mixFunction = this._lerp;
				mixFunctionAdditive = this._lerpAdditive;
				setIdentity = this._setAdditiveIdentityNumeric;

				this.buffer = new Float64Array( valueSize * 5 );

		}

		this._mixBufferRegion = mixFunction;
		this._mixBufferRegionAdditive = mixFunctionAdditive;
		this._setIdentity = setIdentity;
		this._origIndex = 3;
		this._addIndex = 4;

		/**
		 * TODO
		 *
		 * @type {number}
		 * @default 0
		 */
		this.cumulativeWeight = 0;

		/**
		 * TODO
		 *
		 * @type {number}
		 * @default 0
		 */
		this.cumulativeWeightAdditive = 0;

		/**
		 * TODO
		 *
		 * @type {number}
		 * @default 0
		 */
		this.useCount = 0;

		/**
		 * TODO
		 *
		 * @type {number}
		 * @default 0
		 */
		this.referenceCount = 0;

	}
Constructs a new property mixer.

@param {PropertyBinding} binding - The property binding.
@param {string} typeName - The keyframe track type name.
@param {number} valueSize - The keyframe track value size.