util: add toFloat function.

lib/btc/amount.js

@@ -334,8 +334,9 @@ Amount.value = function value(str) {
  */
 
 Amount.encode = function encode(value, exp, num) {
-  const str = util.toFixed(value, exp);
+  if (num)
-  return num ? Number(str) : str;
+    return util.toFloat(value, exp);
+  return util.toFixed(value, exp);
 };
 
 /**

lib/utils/util.js

@@ -834,7 +834,7 @@ util.memoryUsage = function memoryUsage() {
  * power of ten (uses no floating point arithmetic).
  * @param {Number} num
  * @param {Number} exp - Number of decimal places.
- * @returns {String}
+ * @returns {String} Fixed number string.
  */
 
 util.toFixed = function toFixed(num, exp) {
@@ -870,26 +870,12 @@ util.toFixed = function toFixed(num, exp) {
   return `${sign}${hi}.${lo}`;
 };
 
-/**
- * Parse a double float number and multiply by a
- * power of ten (uses no floating point arithmetic).
- * @param {Number} num
- * @param {Number} exp - Number of decimal places.
- * @returns {Number}
- */
-
-util.fromFloat = function fromFloat(num, exp) {
-  assert(typeof num === 'number' && isFinite(num));
-  assert(Number.isSafeInteger(exp));
-  return util.fromFixed(num.toFixed(exp), exp);
-};
-
 /**
  * Parse a fixed number string and multiply by a
  * power of ten (uses no floating point arithmetic).
  * @param {String} str
  * @param {Number} exp - Number of decimal places.
- * @returns {Number}
+ * @returns {Number} Integer.
  */
 
 util.fromFixed = function fromFixed(str, exp) {
@@ -947,6 +933,32 @@ util.fromFixed = function fromFixed(str, exp) {
   return sign * (hi * mult + lo);
 };
 
+/**
+ * Convert int to float and reduce by a power
+ * of ten (uses no floating point arithmetic).
+ * @param {Number} num
+ * @param {Number} exp - Number of decimal places.
+ * @returns {Number} Double float.
+ */
+
+util.toFloat = function toFloat(num, exp) {
+  return Number(util.toFixed(num, exp));
+};
+
+/**
+ * Parse a double float number and multiply by a
+ * power of ten (uses no floating point arithmetic).
+ * @param {Number} num
+ * @param {Number} exp - Number of decimal places.
+ * @returns {Number} Integer.
+ */
+
+util.fromFloat = function fromFloat(num, exp) {
+  assert(typeof num === 'number' && isFinite(num));
+  assert(Number.isSafeInteger(exp));
+  return util.fromFixed(num.toFixed(exp), exp);
+};
+
 /*
  * Helpers
  */

test/utils-test.js

@@ -72,31 +72,17 @@ describe('Utils', function() {
   });
 
   it('should convert satoshi to btc', () => {
-    let btc = Amount.btc(5460);
+    assert.strictEqual(Amount.btc(5460), '0.0000546');
-    assert.strictEqual(btc, '0.0000546');
+    assert.strictEqual(Amount.btc(54678 * 1000000), '546.78');
-
+    assert.strictEqual(Amount.btc(5460 * 10000000), '546.0');
-    btc = Amount.btc(54678 * 1000000);
-    assert.strictEqual(btc, '546.78');
-
-    btc = Amount.btc(5460 * 10000000);
-    assert.strictEqual(btc, '546.0');
   });
 
   it('should convert btc to satoshi', () => {
-    let btc = Amount.value('0.0000546');
+    assert.strictEqual(Amount.value('0.0000546'), 5460);
-    assert.strictEqual(btc, 5460);
+    assert.strictEqual(Amount.value('546.78'), 54678 * 1000000);
-
+    assert.strictEqual(Amount.value('546'), 5460 * 10000000);
-    btc = Amount.value('546.78');
+    assert.strictEqual(Amount.value('546.0'), 5460 * 10000000);
-    assert.strictEqual(btc, 54678 * 1000000);
+    assert.strictEqual(Amount.value('546.0000'), 5460 * 10000000);
-
-    btc = Amount.value('546');
-    assert.strictEqual(btc, 5460 * 10000000);
-
-    btc = Amount.value('546.0');
-    assert.strictEqual(btc, 5460 * 10000000);
-
-    btc = Amount.value('546.0000');
-    assert.strictEqual(btc, 5460 * 10000000);
 
     assert.doesNotThrow(() => {
       Amount.value('546.00000000000000000');
@@ -122,10 +108,14 @@ describe('Utils', function() {
       Amount.value('190071992.54740991');
     });
 
+    assert.strictEqual(0.15645647 * 1e8, 15645646.999999998);
     assert.strictEqual(parseFloat('0.15645647') * 1e8, 15645646.999999998);
-    assert.strictEqual(util.fromFloat(0.15645647, 8), 15645647);
+    assert.strictEqual(15645647 / 1e8, 0.15645647);
+
     assert.strictEqual(util.fromFixed('0.15645647', 8), 15645647);
     assert.strictEqual(util.toFixed(15645647, 8), '0.15645647');
+    assert.strictEqual(util.fromFloat(0.15645647, 8), 15645647);
+    assert.strictEqual(util.toFloat(15645647, 8), 0.15645647);
   });
 
   it('should write/read new varints', () => {