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node_modules/core-js/modules/es.number.to-exponential.js

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+'use strict';
+var $ = require('../internals/export');
+var uncurryThis = require('../internals/function-uncurry-this');
+var toIntegerOrInfinity = require('../internals/to-integer-or-infinity');
+var thisNumberValue = require('../internals/this-number-value');
+var $repeat = require('../internals/string-repeat');
+var log10 = require('../internals/math-log10');
+var fails = require('../internals/fails');
+
+var $RangeError = RangeError;
+var $String = String;
+var $isFinite = isFinite;
+var abs = Math.abs;
+var floor = Math.floor;
+var pow = Math.pow;
+var round = Math.round;
+var nativeToExponential = uncurryThis(1.0.toExponential);
+var repeat = uncurryThis($repeat);
+var stringSlice = uncurryThis(''.slice);
+
+// Edge 17-
+var ROUNDS_PROPERLY = nativeToExponential(-6.9e-11, 4) === '-6.9000e-11'
+  // IE11- && Edge 14-
+  && nativeToExponential(1.255, 2) === '1.25e+0'
+  // FF86-, V8 ~ Chrome 49-50
+  && nativeToExponential(12345, 3) === '1.235e+4'
+  // FF86-, V8 ~ Chrome 49-50
+  && nativeToExponential(25, 0) === '3e+1';
+
+// IE8-
+var throwsOnInfinityFraction = function () {
+  return fails(function () {
+    nativeToExponential(1, Infinity);
+  }) && fails(function () {
+    nativeToExponential(1, -Infinity);
+  });
+};
+
+// Safari <11 && FF <50
+var properNonFiniteThisCheck = function () {
+  return !fails(function () {
+    nativeToExponential(Infinity, Infinity);
+    nativeToExponential(NaN, Infinity);
+  });
+};
+
+var FORCED = !ROUNDS_PROPERLY || !throwsOnInfinityFraction() || !properNonFiniteThisCheck();
+
+// `Number.prototype.toExponential` method
+// https://tc39.es/ecma262/#sec-number.prototype.toexponential
+$({ target: 'Number', proto: true, forced: FORCED }, {
+  toExponential: function toExponential(fractionDigits) {
+    var x = thisNumberValue(this);
+    if (fractionDigits === undefined) return nativeToExponential(x);
+    var f = toIntegerOrInfinity(fractionDigits);
+    if (!$isFinite(x)) return String(x);
+    // TODO: ES2018 increased the maximum number of fraction digits to 100, need to improve the implementation
+    if (f < 0 || f > 20) throw $RangeError('Incorrect fraction digits');
+    if (ROUNDS_PROPERLY) return nativeToExponential(x, f);
+    var s = '';
+    var m = '';
+    var e = 0;
+    var c = '';
+    var d = '';
+    if (x < 0) {
+      s = '-';
+      x = -x;
+    }
+    if (x === 0) {
+      e = 0;
+      m = repeat('0', f + 1);
+    } else {
+      // this block is based on https://gist.github.com/SheetJSDev/1100ad56b9f856c95299ed0e068eea08
+      // TODO: improve accuracy with big fraction digits
+      var l = log10(x);
+      e = floor(l);
+      var n = 0;
+      var w = pow(10, e - f);
+      n = round(x / w);
+      if (2 * x >= (2 * n + 1) * w) {
+        n += 1;
+      }
+      if (n >= pow(10, f + 1)) {
+        n /= 10;
+        e += 1;
+      }
+      m = $String(n);
+    }
+    if (f !== 0) {
+      m = stringSlice(m, 0, 1) + '.' + stringSlice(m, 1);
+    }
+    if (e === 0) {
+      c = '+';
+      d = '0';
+    } else {
+      c = e > 0 ? '+' : '-';
+      d = $String(abs(e));
+    }
+    m += 'e' + c + d;
+    return s + m;
+  }
+});